(defun main (&rest argv)
  (declare (ignore argv))
  (let* ((n (read))
         (xs (loop repeat n collect (read)))
         (num (make-hash-table))
         (ans 0))
    (dolist (i xs)
      (incf (gethash i num 0)))
    (maphash (lambda (key val)
               (declare (ignore key))
               (when (= val 1)
                     (incf ans)))
             num)
    (format t "~A~%" ans)))

(main)