sub pickingNumbers {
    my $aa = shift;

    my $max = 0;
    my @a = sort {$a <=> $b} @$aa;
    for (my $i = 0; $i < scalar(@a); $i++) {
        my $cnt = 0;
        for (my $j = $i+1; $j < scalar(@a); $j++) {
            if (abs($a[$i] - $a[$j]) <= 1) {
                $cnt++;
            }            
        }
        $max = $cnt if ($cnt > $max);
    }
    return ++$max;
}