diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -15,7 +15,7 @@
             cnt += 1
             for j in range(m):
                 if grid[i][j] == "o":
-                    exist[j] == True
+                    exist[j] = True
 
     if all(exist):
         ans = min(ans, cnt)
