diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -17,7 +17,7 @@
 
         cnt = 0
         for i in range(len(c)):
-            if c[i] == "0":
+            if c[i] == "1":
                 if not (a[i] == c[i] or b[i] == c[i]):
                     cnt += 1
             else:
