my (%f_count,%n_count);

for my $file (@files) {
    open( my $fh, '<', $file ) or die "Couldn't read '$file': $!";
    
    while (my $line = <$fh>) {
        chomp $line;
        next unless $line;
        my ($name,$number) = split(',',$line);
        $n_count{$name}++;
        $f_count{$name}{$file}++;
    }
}

##</code><code>##

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";
}