6. Password Generator

<?php
$first = readline();
$second = readline();
strtoupper($second);
$third = readline();
strtolower($third);
$fourth = readline();
$fifth = readline();
$sixth = readline();

$num = readline();

       $counter = 0;
        for ($i = 1; $i <= $first; $i++) {
            for ($j = 'A'; $j <= $second; $j++) {
                for ($k = 'a'; $k <= $third; $k++) {
                    for ($l = 1; $l <= $fourth; $l++) {
                        for ($m = 1; $m <= $fifth; $m++) {
                            for ($o = 1; $o <= $sixth; $o++) {
                                $counter++;
                                if($counter == $num) {
                                  printf("%s%s%s%s%s%s",$i,$j,$k,$l,$m,$o);

                                }
                            }
                        }
                    }
                }
            }
        }

        if ($counter < $num) {
            echo("No password on this position");
        }