(define (cons a b)
  (* (power 2 a) (power 3 b)))

(define (power x n)
  (if (= n 0)
      1
      (* x (power x (- n 1)))))

(define (iter x n p)
  (if (> (remainder x n) 0)
      p
      (iter (quotient x n) n (+ 1 p))))

(define (car z)
  (iter z 2 0))

(define (cdr z)
  (iter z 3 0))