#| BEGIN (Write your solution here) |#
(define (make-semaphore n)
    (let ((count n)
          (count-mutex (make-mutex)))
      (define (the-semaphore m)
        (cond ((eq? m 'acquire)
               (count-mutex 'acquire)
               (if (> count 0)
                   (begin
                     (set! count (- count 1))
                     (count-mutex 'release))
                   (begin
                     (count-mutex 'release)
                     (the-semaphore 'acquire))))
              ((eq? m 'release)
               (count-mutex 'acquire)
               (if (= count n)
                   (count-mutex 'release)
                   (begin
                     (set! count (+ count 1))
                     (count-mutex 'release))))
              ((eq? m 'count)
               count)))
      the-semaphore))
#| END |#