public function max($input, $key, $max, $lang)
    {
        $lang = $this->custom('max', $lang);
        if (strlen($input[$key]) > $max) {
            return preg_replace_callback('/(:field)(.*)(\:num)/i',
            function ($m) use ($key, $max) {
                return $key.$m[2].$max;
            }, $lang);
        }
    }