(defun C+ (x y)
  (cons (+ (car x) (car y)) (+ (cdr x) (cdr y))))

(defun C- (x y)
  (cons (- (car x) (car y)) (+ (cdr x) (cdr y))))

(defun CC (x)
  (cons (car x) (- (cdr x))))

(defun c* (x y)
  (cons (- (* (car x) (car y))
	   (* (cdr x) (cdr y)))
	(+ (* (car x) (cdr y))
	   (* (cdr x) (car y)))))

(defun C/ (x y)
  (let* ((ycc (cc y))
	 (z (c* x ycc))
	 (y2 (car (* y ycc))))
    (rplaca z (/ (car z) y2))
    (rplacd z (/ (cdr z) y2))
    z))