my $num_of_files = scalar @files;
my $min = 25;
my @candidates = grep { $n_count{$_} >= $min } keys %n_count;

for my $name (@candidates) {
	my $in_files = scalar keys %{ $f_count{$name} };
	next unless $in_files == $num_of_files;
	print "$name\n";
}