;;; This is the code for ps1.

(defun p1 (x y)
  (+ (p2 x y) (p3 x y)))

(defun p2 (z w)
  (* z w))

(defun p3 (a b)
  (+ (p2 a) (p2 b)))

(defun fact (n)
  (if (= n 0)
      (* n (fact (- n 1)))))