<?phpif($_GET['no']){ $db =dbconnect();if(preg_match("/ |\/|\(|\)|\||&|select|from|0x/i",$_GET['no'])) exit("no hack"); $result =mysqli_fetch_array(mysqli_query($db,"select id from chall18 where id='guest' and no=$_GET[no]")); // admin's no = 2if($result['id']=="guest") echo"hi guest";if($result['id']=="admin"){solve(18);echo"hi admin!"; }}?>