(define loops '(
 (define (f x y)
   (if (op >= (op + x 1) y)
       x
       (call f (op + x 1) y)))))

(define large '(
 (define (f x y)
   (if (op = x 0)
       y
       (op +  (call f (op - x 1) y) (call f (op - x 1) y))))))