diff --git a/source/substring_hash_segment_tree.h b/source/substring_hash_segment_tree.h
index 6d954a5..129cb2f 100644
--- a/source/substring_hash_segment_tree.h
+++ b/source/substring_hash_segment_tree.h
@@ -1,6 +1,8 @@
 #pragma once
 #include "common.h"
 
+#define mod (ll)(1e9 + 7)
+
 struct Node {
 	ll h, p;
 	Node(char ch) { h = ch; p = 26; }