diff --git a/Swap/flamingo-contract-swap/FlamingoSwapFactory/FlamingoSwapFactoryContract.Admin.cs b/Swap/flamingo-contract-swap/FlamingoSwapFactory/FlamingoSwapFactoryContract.Admin.cs
index f2173c1..f8057ac 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapFactory/FlamingoSwapFactoryContract.Admin.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapFactory/FlamingoSwapFactoryContract.Admin.cs
@@ -52,6 +52,7 @@ public static byte[] Upgrade(byte[] newScript, byte[] paramList, byte returnType
             Assert(Runtime.CheckWitness(GetAdmin()), "upgrade: CheckWitness failed!");
 
             byte[] newContractHash = Hash160(newScript);
+            Assert(Blockchain.GetContract(newContractHash).Serialize().Equals(new byte[] { 0x00, 0x00 }), "upgrade: The contract already exists");
 
             Contract newContract = Contract.Migrate(newScript, paramList, returnType, cps, name, version, author, email, description);
             Runtime.Notify("upgrade", ExecutionEngine.ExecutingScriptHash, newContractHash);
diff --git a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Admin.cs b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Admin.cs
index 339961d..ee98b01 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Admin.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Admin.cs
@@ -61,6 +61,7 @@ public static byte[] Upgrade(byte[] newScript, byte[] paramList, byte returnType
 
             var me = ExecutionEngine.ExecutingScriptHash;
             byte[] newContractHash = Hash160(newScript);
+            Assert(Blockchain.GetContract(newContractHash).Serialize().Equals(new byte[] { 0x00, 0x00 }), "upgrade: The contract already exists");
 
             var r = ReservePair;
             SafeTransfer(Token0, me, newContractHash, r.Reserve0);
diff --git a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Nep5.cs b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Nep5.cs
index bbbb718..ce90787 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Nep5.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.Nep5.cs
@@ -25,8 +25,6 @@ partial class FlamingoSwapPairContract
         [DisplayName("name")]
         public static string Name() => "Exchange Pair"; //name of the token
 
-        [DisplayName("symbol")]
-        public static string Symbol() => "Temp-AB"; //symbol of the token
 
 
         [DisplayName("supportedStandards")]
@@ -70,7 +68,7 @@ private static bool Transfer(byte[] from, byte[] to, BigInteger amount, byte[] c
         {
             //Check parameters
             Assert(from.Length == 20 && to.Length == 20, "The parameters from and to SHOULD be 20-byte addresses.");
-            Assert(amount > 0, "The parameter amount MUST be greater than 0.");
+            Assert(amount >= 0, "The parameter amount MUST be greater than 0.");
 
             if (!Runtime.CheckWitness(from) && from.AsBigInteger() != callscript.AsBigInteger())
                 return false;
@@ -81,6 +79,7 @@ private static bool Transfer(byte[] from, byte[] to, BigInteger amount, byte[] c
             if (from == to)
                 return true;
 
+
             //Reduce payer balances
             if (fromAmount == amount)
                 asset.Delete(from);
diff --git a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.cs b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.cs
index baca445..43f417b 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapPair/FlamingoSwapPairContract.cs
@@ -30,6 +30,10 @@ partial class FlamingoSwapPairContract : SmartContract
         /// </summary>
         static readonly byte[] Token1 = "cbad1e6082cb71f336939934f21e5929a5c6d7ff".HexToBytes();
 
+
+        [DisplayName("symbol")]
+        public static string Symbol() => "E-AB"; //symbol of the token
+
         #endregion
 
 
@@ -45,6 +49,9 @@ partial class FlamingoSwapPairContract : SmartContract
         ///// </summary>
         //static readonly byte[] Token1 = "7c76490fc79a8a47068b904e83d78c0292590fd4".HexToBytes();
 
+        //[DisplayName("symbol")]
+        //public static string Symbol() => "E-BC"; //symbol of the token
+
         #endregion
 
 
diff --git a/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.Admin.cs b/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.Admin.cs
index ef0bbcc..4216144 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.Admin.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.Admin.cs
@@ -54,6 +54,7 @@ public static byte[] Upgrade(byte[] newScript, byte[] paramList, byte returnType
             Assert(Runtime.CheckWitness(GetAdmin()), "upgrade: CheckWitness failed!");
 
             byte[] newContractHash = Hash160(newScript);
+            Assert(Blockchain.GetContract(newContractHash).Serialize().Equals(new byte[] { 0x00, 0x00 }), "upgrade: The contract already exists");
 
             Contract newContract = Contract.Migrate(newScript, paramList, returnType, cps, name, version, author, email, description);
             Runtime.Notify("upgrade", ExecutionEngine.ExecutingScriptHash, newContractHash);
diff --git a/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.cs b/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.cs
index 9c6bb25..00d9a49 100644
--- a/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.cs
+++ b/Swap/flamingo-contract-swap/FlamingoSwapRouter/FlamingoSwapRouterContract.cs
@@ -114,6 +114,7 @@ public static BigInteger[] AddLiquidity(byte[] sender, byte[] tokenA, byte[] tok
                 {
                     //B超出期望最大值，按照 TokenB 期望最大值计算 TokenA 的注入量
                     var estimatedA = Quote(amountBDesired, reserveB, reserveA);
+                    Assert(estimatedA <= amountADesired, "Excess A Amount");
                     Assert(estimatedA >= amountAMin, "Insufficient A Amount");
                     amountA = estimatedA;
                     amountB = amountBDesired;