#| BEGIN (Write your solution here) |#

(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 (adjoin-set x set)
    (cond ((null? set) (list x))
          ((< x (car set)) (cons x set))
          ((> x (car set)) (cons (car set) (adjoin-set x (cdr set))))
          ((= x (car set)) set)
          ((null? (cdr set)) (append set (list x)))
    )
)
#| END |#