#!/usr/bin/perl -w
use strict;

my $data = read_input();
my $sets = scan($data);
for (@$sets) {
  printf "{ %s }\n", join ' ', sort { $a <=> $b } @$_;
}

sub read_input {
  my @data;
  local $_;
  while (<DATA>) { 
    push @data, [ grep defined, split /\s+/ ];
  } 
  \@data;
}

sub scan {
  my $data = shift;
  my(%matches, %results);
  for my $index (0 .. $#$data) { 
    my @equal;
    my $these = $data->[$index];
    for my $key (keys %matches) {
      my $compare = $matches{$key};
      if (grep exists $compare->{$_}, @$these) {
        push @equal, $key;
      }
    }

    $results{$index} = [ $index, map @{ delete $results{$_} }, @equal ];
    $matches{$index} = { 
      map(($_ => 1), @$these),
      map %{ delete $matches{$_} }, @equal
    };  
  } 
  [ values %results ];
}

__END__
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