#!/usr/bin/perl
use strict;
use List::Util qw(max sum);

open my $fin, '<', 'input.txt' or die;
open my $fout, '>', 'output.txt' or die;

my $n = <$fin>;
my $k = <$fin>;
my %names;

    for (my $j = 0; $j < $n; $j++) {

        my %temp = ();

        for (my $i = 0; $i < $k; $i++) {

            my $fish_name = <$fin>;
            $temp{$fish_name}++;

        }

        foreach(keys %temp) {
            $names{$_} = max($names{$_}, $temp{$_});
        }

        $k = <$fin>;
    }
    print $fout sum(values %names);

close $fin or die;
close $fout or die;