defmodule Main do

  def main do
    [a, b] = IO.gets("") |> String.trim() |> String.split(" ")
    a = String.to_integer(a)

    multiplication(a, b) |> IO.puts()
  end

  @doc """
  Multiplication

  ## Examples

      iex> Multiplication3.multiplication(198, "1.10")
      217
      iex> Multiplication3.multiplication(1, "0.01")
      0
      iex> Multiplication3.multiplication(1000000000000000, "9.99")
      9990000000000000

  """
  def multiplication(a, b) do
    b = b |> String.codepoints() |> Enum.reject(& &1 == ".") |> Enum.join |> String.to_integer()
    (a * b) |> div(100)
  end

end