public static function getNest($input, $open = "(", $close = ")"){
         
         $pattern = '#\\'.$open.'((?>[^\\'.$open.'[\\'.$close.']+)|(?R))*\\'.$close.'#';
         $count = preg_match_all($pattern, $input, $matches);
         
         if($count > 0)
                return $matches[0][0];
         
    return false;
    }