#| BEGIN (Введите свое решение) |#
(define (make-point x y) (cons x y))
(define (x-point x) (car x))
(define (y-point x) (cdr x))

(define (make-segment a b) (cons a b))
(define (start-segment x) (car x))
(define (end-segment x) (cdr x))

(define (midpoint-segment l) (make-point (/ (+ (x-point (start-segment l)) 
                                               (x-point (end-segment l))) 
                                            2)
                                         (/ (+ (y-point (start-segment l)) 
                                               (y-point (end-segment l))) 
                                            2)))

(define (print-point p)
  (newline)
  (display "(")
  (display (x-point p))
  (display ",")
  (display (y-point p))
  (display ")"))
#| END |#