sub getMoneySpent {
    my ($keyboard, $drives, $b) = @_;
    
    my $most_expensive = 0;
    my $keyb = 0;
    my $device = 0;
    for (my $i = 0; $i < scalar(@$keyboard); $i++) {
        for (my $j = 0; $j < scalar(@$drives); $j++) {
            if ($keyboard->[$i] < $b || $drives->[$j] < $b) {
                my $sum = $keyboard->[$i] + $drives->[$j];
                if ($sum > $most_expensive && $sum <= $b) {
                    $most_expensive = $sum;
                    $keyb = $keyboard->[$i];
                    $device = $drives->[$j];
                }                
            }            
        }
    }
    return (($keyb + $device) > 0) ? $keyb + $device : -1;
}