sub round_up {
    my $num = shift || die "Please, specify target number!";

    my $length = length($num);
    my $first = substr($num, 0, 1);

    if($length > 2) {
        my $rest = substr($num, 1);
        $num = $first.('0'x($length - 1)) +
                    ((substr($rest, 0, 1) + 1).('0'x(length($rest) - 1)));
    } elsif($length == 2) {
        $num = (substr($num, 0, 1) + 1) . ('0'x($length-1));
    } else {
        $num = 10;
    }

    return $num;
}