diff --git a/504_square_on_the_inside.py b/504_square_on_the_inside.py
index 7f102d8..5e3bab2 100644
--- a/504_square_on_the_inside.py
+++ b/504_square_on_the_inside.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 
-from fractions import gcd
+from math import gcd
 from itertools import combinations_with_replacement as combs
 from math import sqrt