defmodule Main do
  def main do
    d = IO.read(:line) |> String.trim |> String.to_integer;
    [a, b] = IO.read(:line) |> String.trim |> String.split(" ") |> Enum.map(&String.to_integer/1)
    x = d;
    IO.puts x * a + (d - x) * b ;

  end
end