defmodule Main do
  def main do
    1..3
    |> Enum.map(fn _ ->
      IO.read(:line)
      |> String.trim()
      |> String.to_integer()
    end)
    |> solve
    |> IO.puts()
  end

  defp solve([x, y, l]) do
    (cond do
       y < 0 -> 2
       x == 0 -> 0
       true -> 1
     end +
       cond do
         y == 0 -> 0
         true -> (abs(y) / l) |> Float.ceil()
       end +
       cond do
         x == 0 -> 0
         true -> (abs(x) / l) |> Float.ceil()
       end)
    |> trunc
  end
end