defmodule Main do
  def input, do: IO.read(:line) |> String.trim
  def ii, do: input() |> String.to_integer
  def li, do: input() |> String.split |> Enum.map(&String.to_integer/1)

  def main do
    _n = ii()
    p = li()

    if Enum.member?(p, 0) do
      0
    else
      for x <- p, reduce: 1 do
        acc -> rem(acc * x, 9)
      end
      |> then(fn x -> if x == 0, do: 9, else: x end)
    end
    |> IO.puts
  end
end