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

    new_a = String.to_integer(a)
    new_b = String.to_float(b)

    {num, _} =
      (new_a * new_b)
      |> Float.floor(1)
      |> trunc()
      |> to_string()
      |> Integer.parse()

    IO.inspect(num)
  end
end