#! perl
use Modern::Perl;
use Set::Scalar;

my $class_callback = sub { join(' ', sort { $a <=> $b } $_[0]->elements) };
Set::Scalar->as_string_callback($class_callback);

my @sets;

for (my $i = 0; <DATA>;)
{
    chomp;
    my $new_set = Set::Scalar->new(split /\s+/);
    my $merged  = 0;

    for my $j (0 .. $i - 1)
    {
        if ($new_set->intersection($sets[$j]))
        {
            $sets[$j] = $sets[$j]->union($new_set);
            $merged   = 1;
            last;
        }
    }

    $sets[$i++] = $new_set unless $merged;
}

print '(', $_, ")\n" for @sets;

__DATA__
1 2 4 
2 3 4
3 7
4 6
5 10 11 12 13
6
7 1