diff --git a/001_two_sum/two_sum.cc b/001_two_sum/two_sum.cc
index c06f0b4..47633ee 100644
--- a/001_two_sum/two_sum.cc
+++ b/001_two_sum/two_sum.cc
@@ -1,4 +1,4 @@
-#include <bits/stdc++.h>
+#include <bits/stdc++.h> // header file 
 
 using namespace std;