diff --git a/reasoning_gym/algorithmic/word_sorting.py b/reasoning_gym/algorithmic/word_sorting.py
index 1218f447..5e32d031 100644
--- a/reasoning_gym/algorithmic/word_sorting.py
+++ b/reasoning_gym/algorithmic/word_sorting.py
@@ -1,5 +1,6 @@
 """Word sorting task generator"""
 
+import re
 from dataclasses import dataclass
 from enum import Enum
 from random import Random