diff --git a/kujin-CSharp/Leet/2609 Leet.cpp b/kujin-CSharp/Leet/2609 Leet.cpp
new file mode 100644
index 0000000..8b2dac4
--- /dev/null
+++ b/kujin-CSharp/Leet/2609 Leet.cpp	
@@ -0,0 +1,29 @@
+class Solution {
+public:
+    int findTheLongestBalancedSubstring(string S) {
+        int Cnt0=0;
+        int Cnt1=0;
+        int MaxNum=0;
+        int N=S.length();
+        for(int i=0;i < N; i++)
+        {
+            if(i!=0 && S[i-1]=='1' && S[i]=='0')
+            {
+                Cnt0=1;
+                Cnt1=0;
+            }
+            else{
+                if(S[i]=='0')
+                {
+                    Cnt0++;
+                }
+                else
+                {
+                    Cnt1++;
+                }
+                MaxNum = max(MaxNum,min(Cnt1,Cnt0)*2);
+            }
+        }
+        return MaxNum;
+    }
+};
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