diff --git a/atcoder/lazysegtree.py b/atcoder/lazysegtree.py
index b2337f4..0a49053 100644
--- a/atcoder/lazysegtree.py
+++ b/atcoder/lazysegtree.py
@@ -62,7 +62,7 @@ def prod(self, left: int, right: int) -> typing.Any:
             if ((left >> i) << i) != left:
                 self._push(left >> i)
             if ((right >> i) << i) != right:
-                self._push(right >> i)
+                self._push((right - 1) >> i)
 
         sml = self._e
         smr = self._e