diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -13,6 +13,6 @@
         cnt2 = Counter(t)
         sm = 0
         cnt = cnt1 - cnt2 + (cnt2 - cnt1)
-        for i in undf_obj.values():
+        for i in cnt.values():
             sm += i
         return sm
