<?php 
highlight_file('2.php');
$key='flag{********************************}';
$IsMatch= preg_match("/wel.*come\_.{2,4}\_\/hongyaa\/:(.*key)[a-z][[:punct:]]/i", trim($_GET["id"]), $match);
if( $IsMatch ){ 
  die('key: '.$key);
}
?>
Notice: Undefined index: id in /opt/lampp/htdocs/47/index.php on line 4