defmodule Main do
  def main do
    IO.read(:line)
    |> String.split()
    |> solve
    |> IO.puts()
  end

  defp solve([w, h, c]) do
    d =
      cond do
        c == "B" -> "W"
        true -> "B"
      end

    0..((h |> String.to_integer()) - 1)
    |> Enum.map(fn i ->
      0..((w |> String.to_integer()) - 1)
      |> Enum.map(fn j ->
        cond do
          (i - j) |> rem(2) == 0 -> c
          true -> d
        end
      end)
      |> Enum.join()
    end)
    |> Enum.join("\n")
  end
end