let () =
  let x, y, l = Scanf.scanf "%d %d %d " (fun x y l -> x, y, l) in
  let move v = v / l + v mod l in
  let d = (if x = 0 then 0 else if x > 0 then 1 + move x else 1 + move (-x))
    + (if y >= 0 then move y else 1 + move (-y)) in
  Printf.printf "%d\n" d