(define (solve Aw Ab Bw Bb C D)
  (let* ((use-black (min C Ab)) (use-white (- C use-black)))
    (let ((Aw (- Aw use-white)) (Ab (- Ab use-black)) (Bw (+ Bw use-white)) (Bb (+ Bb use-black)))
      (let ((use-white (min D Bw)))
	(+ Aw use-white)))))

(display (solve (read) (read) (read) (read) (read) (read)))
(newline)