my %freq;
while (<$fh>) {
    chomp;
    $freq{$_}++ for split //;
}
my $tot = sum(values %freq);
for (keys %freq) {
    $freq{$_} = 1 - ($freq{$_} / $tot);
}
sub score {
    my ($word) = @_;
    my $score = 0;
    $score += $freq{$_} for split //, $word;
    return $score;
}