;        (in-package "COMMON-LISP")
;        
;        (defun 1+ (x) (+ x 1))
;        (defun 1- (x) (- x 1))
;        (defun evenp (x) (eql (mod x 2) 0))
;        (defun oddp (x) (eql (mod x 2) 1))
;        (defun zerop (x) (eql x 0))
