diff --git a/arrays_and_strings/str-longest-non-repeating.py b/arrays_and_strings/str-longest-non-repeating.py
index 62c1008..42c8704 100644
--- a/arrays_and_strings/str-longest-non-repeating.py
+++ b/arrays_and_strings/str-longest-non-repeating.py
@@ -1,4 +1,8 @@
-### find the length of the longest substring without repeating characters
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+# find the length of the longest substring without repeating characters
 
 
 def length_longest_substring(s: str) -> int: