diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -14,7 +14,7 @@
     for i in range(n):
         if s[i] == t[i]:
             ans += "0"
-        elif s[i] == 0:
+        elif s[i] == "0":
             if hum_t < cnt // 2:
                 ans += "0"
                 hum_t += 1
