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)
    cond do
      a < b -> IO.puts d * (a - b) + b * d
      a >= b -> IO.puts d * b
    end
  end
end