#| BEGIN (Введите свое решение) |#
(define (adjoin-set x set)
  (cond ((element-of-set? x set) set)
        ((null? set) (cons x set))
        ((> x (car set)) (cons (car set) (adjoin-set x (cdr set))))
        ((< x (car set)) (cons x set))))

(define (element-of-set? x set)
  (cond ((null? set) #f)
        ((= x (car set)) #t)
        ((< x (car set)) #f)
        (else (element-of-set? x (cdr set)))))

(define (union-set set1 set2)
  (cond [(null? set1) set2]
        [(element-of-set? (car set1) set2) (union-set (cdr set1) set2)]
        [else (union-set (cdr set1) (adjoin-set (car set1) set2))]))



#| END |#