defmodule Main do
  def main do
    IO.read(:line)
    |> String.split()
    |> Enum.map(&String.to_integer/1)
    |> solve
    |> IO.puts()
  end

  def solve([l, k]) do
    s = l |> rem(2 * k)

    (((l - s) |> div(2)) -
       cond do
         s == 0 -> 1
         true -> 0
       end)
    |> (&(&1 - (&1 |> rem(k)))).()
  end
end