diff --git a/buggy.py b/buggy.py
--- a/buggy.py
+++ b/buggy.py
@@ -18,6 +18,6 @@
                 dic[i] = 1
         for i in nums:
             if dic[i] == 1:
-                if (i not in dic) and (i + 1 not in dic):
+                if (i - 1 not in dic) and (i + 1 not in dic):
                     res.append(i)
         return res
