diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -165,7 +165,7 @@
 n, a, b, c, d = mii()
 
 if b == c == 0:
-    if a * d != 0:
+    if a * d == 0:
         print("Yes")
     else:
         print("No")
