diff --git a/15lanqiao/test4.cpp b/15lanqiao/test4.cpp
index 3c0d00c..2da3e71 100644
--- a/15lanqiao/test4.cpp
+++ b/15lanqiao/test4.cpp
@@ -1,3 +1,4 @@
+// lanqiao 19710 R 格式
 #include<bits/stdc++.h>
 using namespace std;
 const int N = 2e3 + 10;