#! perl -slw
use strict;
use Time::HiRes qw[ time ];

$|++;

sub uniq{ my %x; @x{@_} = (); keys %x }

my $start = time;

my @lookup = map{
    my $bits = pack 'C', $_;
    [ grep vec( $bits, $_, 1 ), 0 .. 7 ]
} 0 .. 255;

my %dict;
my %alphabet;
while( <> ) {
    chomp;
    next if length > 8;
    my $r = \%dict;
    undef( $alphabet{ $_ } ), $r = $r->{ $_ } //= {} for sort split '', $_;
    push @{ $r->{_} }, $_;
}
my @alphabet = sort keys %alphabet;

my $best = [ 0, '' ];
my %stats;
sub X {
    my( $first, $soFar, $tree ) = @_;
    if( @$soFar == 8 ) {
        my @words = uniq map {
            my $r = \%dict;
            $r = $r->{ $_ } for @{ $soFar }[ @{ $lookup[ $_ ] } ];
            exists $r->{_} ? @{ $r->{_} } : ();
        } 0 .. 255;
        return unless @words > 1;
        print @{ $best = [ scalar @words, join '', @$soFar ] } if @words > $best->[0];
        $stats{ join '', @$soFar } = \@words;
        return;
    }

    for( grep $_ ge $first, @alphabet ) {
#        next unless exists $tree->{ $_ };
        X( $_, [ @$soFar, $_ ], $tree->{ $_ } );
    }
    return;
}

X( 'a', [], \%dict );

print time - $start; <STDIN>;
printf "[%d] %s : @{[ @{$stats{ $_ }} ]}\n", scalar @{$stats{$_}}, $_ for
    sort{ @{ $stats{ $b } } <=> @{ $stats{ $a } } } keys %stats;