my (@candidate, %freq);
while (<DATA>) {
    chomp;
    my @list = split ' ';
    push @candidate, \@list;
    for my $word (@list) {
        ++$freq{$#candidate}{$_} for split //, $word;
    }
}

for my $idx (keys %freq) {
    my $tot = sum(values %{$freq{$idx}});
    for my $let (keys %{$freq{$idx}}) {
        $freq{$idx}{$let} = ($freq{$idx}{$let} / $tot) * 100;
    }
}

for my $let ('a' .. 'z') {
    my $val = 0;
    for my $idx (0 .. $#candidate) {
        $val += $freq{$idx}{$let} if $freq{$idx}{$let};
    }
    $freq{$let} = $val;
}

my (@solution, %let);
for my $list (@candidate) {
    my ($best, $item) = (0, '');
    for my $word (@$list) {
        my $score = sum(map $freq{$_}, split //, $word);
        ($best, $item) = ($score, $word) if $score > $best;
    }
    ++$let{$_} for split //, $item;
    push @solution, $item;
}
my $best = sum(map {my $n = $let{$_}; ($n * $n + $n) / 2} keys %let);
print "$best : [ @solution ]\n";