#!/usr/bin/perl -l

# http://perlmonks.org/?node_id=551038

use strict;
use warnings;

$_ = 'ABDBACCBBBCBDDBCDCBCCDBABCBABBBBBADACDABACC';

my $n = 0;

$n = length $1 while /((.)\2{$n,})/g;

print "longest run: $n"