diff --git a/src/main.go b/src/main.go
index a1aefcd..141cba0 100644
--- a/src/main.go
+++ b/src/main.go
@@ -56,12 +56,12 @@ func UpdateValidTxns() {
         if err != nil {
             panic(err)
         }
-        if(isValid){
+        if(isValid && !transaction.Vin[0].IsCoinbase){
             fileName := fmt.Sprintf("%s/%s", ValidTxnsDirPath, f.Name())
             os.WriteFile(fileName, byteResult, fs.FileMode(ValidTxnsDirPerm))
             validTxnsCount += 1
         }
-        if(validTxnsCount > 20){
+        if(validTxnsCount > 15){
             break
         }
     }
diff --git a/src/mining/mining.go b/src/mining/mining.go
index 413911c..ebd83b8 100644
--- a/src/mining/mining.go
+++ b/src/mining/mining.go
@@ -121,11 +121,8 @@ func SelectTransactionsFromFolder(validTxnsFolderPath string) []*txn.Transaction
     }
     txnSlice := make([]*txn.Transaction, 0)
 
-    for i, f := range files {
+    for _, f := range files {
         var transaction txn.Transaction
-        if(i == 100) {
-            return txnSlice
-        }
         txnPath := fmt.Sprintf("%s/%s", validTxnsFolderPath, f.Name())
         byteResult, _ := os.ReadFile(txnPath)
         err = json.Unmarshal(byteResult, &transaction)