#!/usr/bin/perl
use strict;
use warnings;

my (%word, %seen);
chomp ( my @line = <DATA> );

for my $index ( 0 .. $#line ) {
    $word{ $_ }{ $index } = undef for split /_/ , $line[ $index ];
}
for ( @line ) {
    my $iter = by_two( $_ );
    while ( my @comb = $iter->() ) {
        my @matches = map { exists $word{ $comb[ 0 ] }{ $_ } ? $_ : () }
            keys %{ $word{ $comb[ 1 ] } }
        ;
        next if @matches < 2;
        my $output = join ' and ' , map { $line[ $_ ] } sort { $a <=> $b } @matches;
        next if $seen{ $output }++;
        print "$output\n";
    }
}
sub by_two {
    my @list  = split /_/ , shift;
    return sub { () } if @list < 2;

    my ($start, $stop, $pos, $done) = (0, $#list, 0, undef);
    return sub {
        return () if $done;
        $pos++;
        if ( $pos > $stop ) {
            $start++;
            $pos = $start + 1;
        }
        $done = 1 if $start == $stop - 1;
        return $list[ $start ], $list[ $pos ];
    }
}
__DATA__
one_two
one_three_two
three_one
one_four
four_three_one