diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -6,7 +6,7 @@
     if S[i] == T[i]:
         cnt += 1
 
-if cnt % 2 == 1:
+if cnt == 3 or cnt == 0:
     print("Yes")
 else:
     print("No")
