sub hackerrankInString {
    my $str = shift;
    my @s = split("", $str);
    my @t = split("", "hackerrank");
    my $pos = -1;
    my @res_arr;
    
    for (my $i = 0; $i <= scalar(@t) - 1; $i++) {
        for (my $j = 0; $j <= scalar(@s) - 1; $j++) {
            if ($t[$i] eq $s[$j] && $pos < $j) {
                $pos = $j;
                push(@res_arr, $s[$j]);
                last;
            }            
        }
    }

    if (join("", @res_arr) eq "hackerrank") {
        return "YES";
    } else { return "NO"; }
}