; - Program 4.24, pg. 124 -

(define fib-it
  (lambda (int acc1 acc2)
    (if (= int 1)
        acc2
        (fib-it (sub1 int) acc2 (+ acc1 acc2)))))

; - End Program -

(define fib2
  (lambda (n)
    (if (< n 2)
	n
	(fib-it n 0 1))))