(defun main (&rest argv)
  (declare (ignorable argv))
  (let* ((n (read))
         (k (read))
         (a (sort (loop repeat n collect (read)) #'>))
         (b (car a)))
    (loop for i from 1 below k
          when (>= (nth i a) 0)
          do (incf b (nth i a)))
    (format t "~d~%" b)))

(main)