(define (divides? a b)
(= (remainder a b) 0))

(define (leap-year? c)
	(cond 	((divides? c 400) #t)
		((divides? c 100) #f)
      		((divides? c 4) #t)
		(else #f)
	)
)

(define (leap-year-logical? c)
 (or (and (divides? c 4) (not (divides? c 100))(divides? c 400)))
)