sub encryption {
    my $s = shift;

    my @parts;
    my $res;
    my $g = 0;
    $s =~ s/\s*//gm;
    my $floor = floor(sqrt(length($s)));
    my $ceeling = ceil(sqrt(length($s)));
    for (my $i = 0; $i < length($s); $i = $i + $ceeling ) {
        push(@parts, substr($s, $i, $ceeling))
    }
    
    while ($g < $ceeling) {
        for (my $j = 0; $j < scalar(@parts); $j++ ) {
            $res .= substr($parts[$j], $g, 1);        
        }
        $res .= " ";
        $g++;
    }   
    
    return $res;
}