diff --git a/src/coin_health_check_team/monitors.rs b/src/coin_health_check_team/monitors.rs
index 251c942..13868fb 100644
--- a/src/coin_health_check_team/monitors.rs
+++ b/src/coin_health_check_team/monitors.rs
@@ -110,52 +110,56 @@ pub async fn collect_valid_usde_trade(
     condition_build.push_str(" AND askPrice > 0");
     condition_build.push_str(" AND askQty > 0");
     // condition_build.push_str(" AND symbol NOT IN (SELECT symbol FROM stop_usdt_trades)");
-    // add fiat and unnessesary coins
-    condition_build.push_str(" AND symbol NOT LIKE 'BUSDUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'USTCUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'FDUSDUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'TUSDUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'USDPUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'SUSDUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'AUDUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'EURUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'GBPUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'USDCUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'BZRXUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'USTUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'NBTUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'VGXUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'RAMPUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'TORNUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'BTTCUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'BTCSTUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'ACAUSDT'");
-    condition_build.push_str(" AND symbol NOT LIKE 'ANCUSDT'");
-
     let condition = Some(condition_build);
 
     // get valid usdt trades
     let usdt_trades =
         select_record(&fetch_table_name, &column_name, &condition, &usdt_trades).await?;
+    
+    // get banned usdt trades
+    #[derive(Debug, FromRow)]
+    struct Symbols {
+        symbol: String,
+    }
+    
+    let table_name = String::from("banned_usdt_trades");
+    let column_name = String::from("symbol");
+    let condition = None;
+    let mut symbols = Symbols {
+        symbol: String::new(),
+    };
+
+    let mut select_result = try_select_record(&table_name, &column_name, &condition, &symbols)
+        .await
+        .unwrap();
+    let mut banned_usdt_trades_set: HashSet<String> = HashSet::new();
+    for element in select_result {
+        banned_usdt_trades_set.insert(element.symbol.clone());
+    }
 
     // filtering usdt trades
     let mut filtered_usdt_trades: HashSet<String> = HashSet::new();
     let mut excluded_usdt_trades: HashSet<String> = HashSet::new();
     for usdt_trade in usdt_trades {
-        // build update values
-        if let Some(value) = exchange_info_vec.get(&usdt_trade.symbol) {
-            let avg_price: Decimal =
-                rust_decimal::prelude::FromPrimitive::from_f64(usdt_trade.weightedavgprice)
-                    .unwrap();
-            let step_size = value.stepsize;
-            let step_price = decimal_mul(step_size, avg_price);
-            let unit_trade_usdt = crate::coex::assets_managing_team::get_unit_trade_usdt().await;
+        // filtering banned usdt trades
+        if banned_usdt_trades_set.contains(&usdt_trade.symbol) {
+            excluded_usdt_trades.insert(usdt_trade.symbol.clone());
+        } else {
+            // build update values
+            if let Some(value) = exchange_info_vec.get(&usdt_trade.symbol) {
+                let avg_price: Decimal =
+                    rust_decimal::prelude::FromPrimitive::from_f64(usdt_trade.weightedavgprice)
+                        .unwrap();
+                let step_size = value.stepsize;
+                let step_price = decimal_mul(step_size, avg_price);
+                let unit_trade_usdt = crate::coex::assets_managing_team::get_unit_trade_usdt().await;
 
-            // exclude USDT trades whose step_price is over than 1% of unit_trade_usdt
-            if step_price > decimal_mul(unit_trade_usdt, dec!(0.01)) {
-                excluded_usdt_trades.insert(usdt_trade.symbol.clone());
-            } else {
-                filtered_usdt_trades.insert(usdt_trade.symbol.clone());
+                // exclude USDT trades whose step_price is over than 1% of unit_trade_usdt
+                if step_price > decimal_mul(unit_trade_usdt, dec!(0.01)) {
+                    excluded_usdt_trades.insert(usdt_trade.symbol.clone());
+                } else {
+                    filtered_usdt_trades.insert(usdt_trade.symbol.clone());
+                }
             }
         }
     }
diff --git a/src/coin_health_check_team/request_others.rs b/src/coin_health_check_team/request_others.rs
index 231f34f..c92f22d 100644
--- a/src/coin_health_check_team/request_others.rs
+++ b/src/coin_health_check_team/request_others.rs
@@ -7,6 +7,7 @@ use serde::Deserialize;
 use serde_json::Value;
 use sqlx::{Error, FromRow};
 use std::borrow::{Borrow, BorrowMut};
+use std::collections::HashSet;
 use std::sync::Arc;
 use std::collections::HashMap;
 use tokio::{join, sync::Mutex, time::*};
@@ -435,3 +436,137 @@ pub async fn request_exchange_infomation(
 
     Ok(())
 }
+
+pub async fn request_delist_symbols(
+    api_key: &str,
+    secret_key: &str,
+    local_epoch: u128,
+    difference_epoch: i64,
+    client: &Client
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    let mut base_url = String::from("https://api.binance.com/sapi/v1/spot/delist-schedule?");
+
+    // local 시간이 server 시간보다 너무 앞서거나 뒤쳐지면 USER_DATA를 요청할 수 없으므로 local과 server 의 시간 차이만큼을 local에서 빼어 보정한 뒤
+    // 이를 timestamp로 사용한다.
+    let mut timestamp;
+    if difference_epoch >= 0 {
+        timestamp = (local_epoch - difference_epoch as u128).to_string();
+    } else if difference_epoch < 0 {
+        timestamp = (local_epoch - (difference_epoch * -1) as u128).to_string();
+    } else {
+        timestamp = local_epoch.to_string();
+    }
+    let recv_window_size = "20000".to_string(); // default: 5,000ms, Max: 60,000ms
+
+    let mut query_string = String::from("&timestamp=");
+    query_string.push_str(&timestamp);
+    query_string.push_str("&recvWindow=");
+    query_string.push_str(&recv_window_size);
+
+    let signature = HMAC::mac(&query_string.as_bytes(), secret_key.as_bytes());
+
+    query_string.push_str("&signature=");
+    base_url.push_str(&query_string);
+    base_url.push_str(signature.encode_hex::<String>().as_str());
+
+    let mut response = client
+        .get(&base_url)
+        .header("X-MBX-APIKEY", api_key)
+        .send()
+        .await?;
+
+    while !response.status().is_success() {
+        sleep(Duration::from_secs(5)).await;
+        response = client
+            .get(&base_url)
+            .header("X-MBX-APIKEY", api_key)
+            .send()
+            .await?;
+    }
+
+    let mut body = response.text_with_charset("utf-8").await;
+    match body {
+        Ok(T) => {
+            de_deilst_symbol_json(&T).await?;
+        }
+        Err(E) => {
+            log::warn!("request_delist_symbols body failed!: {:?}", E);
+        }
+    }
+
+    Ok(())
+}
+
+async fn de_deilst_symbol_json(
+    body: &String,
+) -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
+    let v: Value = serde_json::from_str(body.as_str())?;
+
+    let into_vec = v.as_array();
+    if into_vec == None {
+        return Err("Err")?;
+    }
+    let mut object_map = &serde_json::map::Map::new();
+    let mut delist_hashset: HashSet<String> = HashSet::new();
+    let mut symbol = String::new();
+    for element in into_vec.unwrap() {
+        object_map = element.as_object().unwrap();
+        let mut object_map_iter = object_map.iter();
+        
+        for element in object_map_iter {
+            match element.0.as_str() {
+                "delistTime" => {
+                },
+                "symbols" => {
+                    if let Some(array) = element.1.as_array() {
+                        for delist_symbol in array {
+                            if let Some(symbol) = delist_symbol.as_str() {
+                                if symbol.ends_with("USDT") && !delist_hashset.contains(symbol) {
+                                    delist_hashset.insert(symbol.to_string()); 
+                                }
+                            }
+                        }
+                    }
+                },
+                _ => {
+                    log::error!("Elements in body msg are changed. Please update both your delist table and vectors.");
+                }
+            }
+        }
+       
+    }
+
+    if delist_hashset.len() != 0 {
+        #[derive(Debug, FromRow)]
+        struct Symbols {
+            symbol: String,
+        }
+        
+        let table_name = String::from("banned_usdt_trades");
+        let column_name = String::from("symbol");
+        let condition = None;
+        let mut symbols = Symbols {
+            symbol: String::new(),
+        };
+
+        let mut select_result = try_select_record(&table_name, &column_name, &condition, &symbols)
+        .await
+        .unwrap();
+        let mut banned_usdt_trades_set: HashSet<String> = HashSet::new();
+        for element in select_result {
+            banned_usdt_trades_set.insert(element.symbol.clone());
+        }
+
+        let insert_column = vec!["symbol"];
+        for element in &delist_hashset {
+            if !banned_usdt_trades_set.contains(element) {
+                let insert_values = vec![element.clone()];
+                insert_one_record(&table_name, &insert_column, &insert_values)
+                .await
+                .unwrap();
+            } 
+        }
+    }
+    
+    Ok(())
+}
diff --git a/src/initialization.rs b/src/initialization.rs
index 9bf91f8..1c3a405 100644
--- a/src/initialization.rs
+++ b/src/initialization.rs
@@ -244,6 +244,60 @@ async fn initialize_database() {
         println!("Ok");
     }
 
+    {
+        print!("table 'banned_usdt_trades'...");
+        io::stdout().flush();
+
+        let table_name = String::from("banned_usdt_trades");
+        let exists_result = exists_table(&table_name).await;
+        let initial_table = vec![
+            ("id", "integer", Some("PK, AI")),
+            ("symbol", "char(20)", None),
+        ];
+        let table_condition = None;
+
+        if exists_result == false {
+            let mut result = new_table(&table_name, &initial_table, &table_condition).await;
+            if result.is_err() {
+                loop {
+                    result = new_table(&table_name, &initial_table, &table_condition).await;
+                    if result.is_ok() {
+                        break;
+                    }
+                    sleep(Duration::from_millis(10)).await;
+                }
+            }
+            let columns = vec!["symbol"];
+            // add fiat and unnessesary coins
+            let value_wrapper = vec![
+                vec![String::from("BUSDUSDT")],
+                vec![String::from("USTCUSDT")],
+                vec![String::from("FDUSDUSDT")],
+                vec![String::from("TUSDUSDT")],
+                vec![String::from("USDPUSDT")],
+                vec![String::from("SUSDUSDT")],
+                vec![String::from("AUDUSDT")],
+                vec![String::from("EURUSDT")],
+                vec![String::from("GBPUSDT")],
+                vec![String::from("USDCUSDT")],
+                vec![String::from("BZRXUSDT")],
+                vec![String::from("USTUSDT")],
+                vec![String::from("NBTUSDT")],
+                vec![String::from("VGXUSDT")],
+                vec![String::from("RAMPUSDT")],
+                vec![String::from("TORNUSDT")],
+                vec![String::from("BTTCUSDT")],
+                vec![String::from("BTCSTUSDT")],
+                vec![String::from("ACAUSDT")],
+                vec![String::from("ANCUSDT")],
+            ];
+            insert_records(&table_name, &columns, &value_wrapper)
+            .await
+            .unwrap();
+        }
+        println!("Ok");
+    }
+
     {
         print!("table 'valid_usdt_trades'...");
         io::stdout().flush();
diff --git a/src/main.rs b/src/main.rs
index 7e939be..dcad773 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -84,9 +84,12 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let tx_task24 = tx_task1.clone(); // for Task#24
     let tx_task25 = tx_task1.clone(); // for Task#25
     let tx_task26 = tx_task1.clone(); // for Task#26
+    let tx_task27 = tx_task1.clone(); // for Task#27
 
-    let (tx1, mut rx1_1) = watch::channel(0); //  local_epoch
-    let (tx2, mut rx2) = watch::channel(0); // epoch_difference
+    let (local_epoch_tx1, mut local_epoch_rx1) = watch::channel(0); //  local_epoch
+    let (epoch_difference_tx1, mut epoch_difference_rx1) = watch::channel(0); // epoch_difference
+    let (local_epoch_tx2, mut local_epoch_rx2) = watch::channel(0); //  local_epoch
+    let (epoch_difference_tx2, mut epoch_difference_rx2) = watch::channel(0); // epoch_difference
 
     // trade fee data
     let mut tradefee_map: HashMap<String, TradeFee> = HashMap::new(); // <symbol, TradeFee>
@@ -278,127 +281,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             let result = rx_task0.recv().await;
 
             match result {
-                Some(1) => {
-                    // print!("\r{1[■] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]}");
-                    print!("\r{:2}", 1);
+                Some(_) => {
+                    print!("\r{:2}", result.unwrap());
                     io::stdout().flush();
                 }
-                Some(2) => {
-                    // print!("\r1[ ] 2[■] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 2);
-                    io::stdout().flush();
-                }
-                Some(3) => {
-                    // print!("\r1[ ] 2[ ] 3[■] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 3);
-                    io::stdout().flush();
-                }
-                Some(4) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[■] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 4);
-                    io::stdout().flush();
-                }
-                Some(5) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[■] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 5);
-                    io::stdout().flush();
-                }
-                Some(6) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[■] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 6);
-                    io::stdout().flush();
-                }
-                Some(7) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[■] 8[] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 7);
-                    io::stdout().flush();
-                }
-                Some(8) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[■ 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 8);
-                    io::stdout().flush();
-                }
-                Some(9) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[■] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 9);
-                    io::stdout().flush();
-                }
-                Some(12) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[■] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 12);
-                    io::stdout().flush();
-                }
-                Some(13) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[■] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 13);
-                    io::stdout().flush();
-                }
-                Some(14) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[■] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 14);
-                    io::stdout().flush();
-                }
-                Some(15) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[■] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 15);
-                    io::stdout().flush();
-                }
-                Some(16) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[■] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 16);
-                    io::stdout().flush();
-                }
-                Some(17) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[■] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 17);
-                    io::stdout().flush();
-                }
-                Some(18) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[■] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 18);
-                    io::stdout().flush();
-                }
-                Some(19) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[■] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 19);
-                    io::stdout().flush();
-                }
-                Some(20) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[■] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 20);
-                    io::stdout().flush();
-                }
-                Some(21) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[■] 22[ ] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 21);
-                    io::stdout().flush();
-                }
-                Some(22) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[■] 23[ ] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 22);
-                    io::stdout().flush();
-                }
-                Some(23) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[■] 24[ ] 25[ ] 26[ ]");
-                    print!("\r{:2}", 23);
-                    io::stdout().flush();
-                }
-                Some(24) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[■] 25[ ] 26[ ]");
-                    print!("\r{:2}", 24);
-                    io::stdout().flush();
-                }
-                Some(25) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[■] 26[ ]");
-                    print!("\r{:2}", 25);
-                    io::stdout().flush();
-                }
-                Some(26) => {
-                    // print!("\r1[ ] 2[ ] 3[ ] 4[ ] 5[ ] 6[ ] 7[ ] 8[ ] 9[ ] 12[ ] 13[ ] 14[ ] 15[ ] 16[ ] 17[ ] 18[ ] 19[ ] 20[ ] 21[ ] 22[ ] 23[ ] 24[ ] 25[ ] 26[■]");
-                    print!("\r{:2}", 26);
-                    io::stdout().flush();
-                }
-                Some(_) => {}
                 None => {}
             }
             sleep(Duration::from_millis(50)).await;
@@ -444,10 +330,14 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
 
             match result {
                 Ok(T) => {
-                    tx1.send(usertime.local_epoch)
-                        .expect("tx1-rx1 channel has been closed.");
-                    tx2.send(usertime.epoch_difference)
-                        .expect("tx2-rx2 channel has been closed.");
+                    local_epoch_tx1.send(usertime.local_epoch)
+                        .expect("local_epoch_tx1-local_epoch_rx1 channel has been closed.");
+                    epoch_difference_tx1.send(usertime.epoch_difference)
+                        .expect("epoch_difference_tx1-epoch_difference_rx1 channel has been closed.");
+                    local_epoch_tx2.send(usertime.local_epoch)
+                        .expect("local_epoch_tx2-local_epoch_rx2 channel has been closed.");
+                    epoch_difference_tx2.send(usertime.epoch_difference)
+                        .expect("epoch_difference_tx2-epoch_difference_rx2 channel has been closed.");
                     tx_task1.send(1).expect("The mpsc channel has been closed.");
                 }
                 Err(E) => {}
@@ -511,10 +401,10 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
             .timeout(tokio::time::Duration::from_millis(3000))
             .build()
             .unwrap();
-            let tx1_changed = rx1_1.changed().await;
-            let tx2_changed = rx2.changed().await;
-            let local_epoch = *rx1_1.borrow();
-            let difference_epoch = *rx2.borrow();
+            let tx1_changed = local_epoch_rx1.changed().await;
+            let tx2_changed = epoch_difference_rx1.changed().await;
+            let local_epoch = *local_epoch_rx1.borrow();
+            let difference_epoch = *epoch_difference_rx1.borrow();
             match tx1_changed {
                 Ok(T) => match tx2_changed {
                     Ok(T) => {
@@ -1424,47 +1314,41 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         }
     });
 
+    // Task#27: request delist symbols
+    tokio::task::spawn(async move {
+        let mut elapsed_time = 0;
+        loop {
+            let instant = Instant::now();
+            let client = ClientBuilder::new()
+            .timeout(tokio::time::Duration::from_millis(3000))
+            .build()
+            .unwrap();
+            let tx1_changed = local_epoch_rx2.changed().await;
+            let tx2_changed = epoch_difference_rx2.changed().await;
+            let local_epoch = *local_epoch_rx2.borrow();
+            let difference_epoch = *epoch_difference_rx2.borrow();
+            
+            
+            let result = request_others::request_delist_symbols(
+                API_KEY,
+                SECRET_KEY,
+                local_epoch,
+                difference_epoch,
+                &client
+            )
+            .await;
+
+            tx_task27.send(27).expect("The mpsc channel has been closed.");
+
+            // sleep as much as the loop recurs per 300 seconds if all operation finished within 300 seconds.
+            elapsed_time = instant.elapsed().as_secs();
+            if 300 > elapsed_time {
+                sleep(Duration::from_secs((300 - elapsed_time) as u64)).await;
+            }
+        }
+    });
+
     loop {
-        // println!("test limit order 실행");
-        // let client = ClientBuilder::new().timeout(Duration::from_millis(1000)).build().unwrap();
-        // limit_order_buy_test(&client).await;
-        // let instant = Instant::now();
-        // let mut elapsed_time = 0;
-        // let capacity_vec_1 = tradefee_vec_capacity.borrow().clone();
-        // let capacity_vec_2 = valid_usdt_trade_vec_capacity.borrow().clone();
-        // let capacity_vec_3 = price_vec_capacity.borrow().clone();
-        // let capacity_vec_4 = candle_1m_vec_capacity.borrow().clone();
-        // let capacity_vec_5 = candle_30m_vec_capacity.borrow().clone();
-        // let capacity_vec_6 = candle_1d_vec_capacity.borrow().clone();
-        // let capacity_vec_7 = candle_1w_vec_capacity.borrow().clone();
-        // let capacity_vec_8 = candle_1mon_vec_capacity.borrow().clone();
-        // let capacity_vec_9 = rt_price_1m_vec_capacity.borrow().clone();
-        // let capacity_vec_10 = rt_price_30m_vec_capacity.borrow().clone();
-        // let capacity_vec_11 = rt_price_1d_vec_capacity.borrow().clone();
-        // let capacity_vec_12 = rt_price_1w_vec_capacity.borrow().clone();
-        // let capacity_vec_13 = rt_price_1mon_vec_capacity.borrow().clone();
-        // let capacity_vec_14 = exchange_info_data_capacity.borrow().clone();
-
-        // println!("@@ {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3}, {:3},", 
-        // capacity_vec_1.capacity(),
-        // capacity_vec_2.capacity(),
-        // capacity_vec_3.capacity(),
-        // capacity_vec_4.capacity(),
-        // capacity_vec_5.capacity(),
-        // capacity_vec_6.capacity(),
-        // capacity_vec_7.capacity(),
-        // capacity_vec_8.capacity(),
-        // capacity_vec_9.capacity(),
-        // capacity_vec_10.capacity(),
-        // capacity_vec_11.capacity(),
-        // capacity_vec_12.capacity(),
-        // capacity_vec_13.capacity(),
-        // capacity_vec_14.capacity());
-
-        // elapsed_time = instant.elapsed().as_millis();
-        //     if 1_000 > elapsed_time {
-        //         sleep(Duration::from_millis((1_000 - elapsed_time) as u64)).await;
-        //     }
     }
 
     Ok(())