(defun read-seq (n) (let ((a (make-array n :initial-element 0)))
    (dotimes (i n) (setf (aref a i) (read)))
    a))

(defun sum (a n) (let ((res 0))
    (dotimes (i n)
        (setf res (+ res (aref a i))))
    res))

(defun main () (let* ((n (read)) (a (read-seq n)) (v (read)))
    (format t "~A~%" (- (sum a n) v))
    ))

(main)