let opert d l =
  let ad = abs d in
  let dl = ad / l in
  if dl * l = ad then dl
  else dl + 1

let () =
  let x = read_int () in
  let y = read_int () in
  let l = read_int () in
  let rotx = if x = 0 then 0 else 1 in
  let roty = if y = 0 then 0 else if y > 0 then 0 else if rotx <> 0 then 1 else 2 in
  print_int ((opert x l) + (opert y l) + rotx + roty);
  print_endline "\n"