defmodule Main do
  def main do
    IO.gets("")

    as =
      IO.gets("")
      |> String.trim()
      |> String.split()
      |> Enum.map(fn s -> String.to_integer(s) end)

    v = IO.gets("") |> String.trim() |> String.to_integer()

    IO.puts(Enum.sum(as) - v)
  end
end