#| BEGIN (Write your solution here) |#
(define (square x)
  (* x x))

(define (even? n)
  (= (remainder n 2) 0))

(define (solution b n)
  (define (iter-step a b n)
    (cond ((= n 0) a)
          ((even? n) (iter-step a (square b) (/ n 2)))
          (else
           (iter-step (* a b) b (- n 1)))))
  (iter-step 1 b n))
#| END |#