diff --git a/Python/snakes-and-ladders.py b/Python/snakes-and-ladders.py
index bb5dfbd07..11c7c4c37 100644
--- a/Python/snakes-and-ladders.py
+++ b/Python/snakes-and-ladders.py
@@ -53,6 +53,9 @@
 # - The board square with number 1 has no snake or ladder.
 # - The board square with number N*N has no snake or ladder.
 
+import collections
+
+
 class Solution(object):
     def snakesAndLadders(self, board):
         """