diff --git a/python/collatz/MaxSequence.py b/python/collatz/MaxSequence.py
index 01e1ddc..7faca5f 100644
--- a/python/collatz/MaxSequence.py
+++ b/python/collatz/MaxSequence.py
@@ -3,7 +3,7 @@
 NUMBER = 500000
 
 def collatz(x):
-    len = 0
+    lengthgth = 0
     while x > 1:
         if x % 2 == 0:
             x = x // 2