#lang lazy

(define Y (λ (f) ((λ (x) (f (x x))) (λ (x) (f (x x))))))

(define Fact
  (Y (λ (fact) (λ (n) (if (zero? n) 1 (* n (fact (- n 1))))))))
(define Fib
  (Y (λ (fib) (λ (n) (if (<= n 1) n (+ (fib (- n 1)) (fib (- n 2))))))))