diff --git a/todo.py b/todo.py
index 185346e..f3c862a 100755
--- a/todo.py
+++ b/todo.py
@@ -73,7 +73,7 @@ def overflow(counter: int, minimum: int, maximum: int) -> int:
     if counter >= maximum:
         return minimum + (counter - maximum)
     if counter < minimum:
-        return maximum - (minimum - counter) 
+        return maximum - (minimum - counter)
     return counter