(define (System.out.println x)
  (begin
    (display x)
    (newline)
  )
)

(let (
      (X (abs (read)))
      (Y (abs (read)))
      (L (read))
     )
  (System.out.println (+ (ceiling (/ Y L)) (+ (ceiling (/ X L)) (ceiling (/ X (+ X 1))))))
)