#! 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 $i = 0; <DATA>; ++$i)
{
    chomp;
    $sets[$i] = Set::Scalar->new(split /\s+/);
}

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

for my $i (reverse 1 .. $#sets)
{
    for my $j (0 .. $i - 1)
    {
        if (defined $sets[$i] &&
            defined $sets[$j] &&
            $sets[$i]->intersection($sets[$j]))
        {
            $sets[$j] = $sets[$i]->union($sets[$j]);
            $sets[$i] = undef;
        }
    }
}

@sets = grep { defined } @sets;

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

__DATA__
1 2 4
7 13
3 5 6
7 8
10 11 12
1 5