defmodule Main do
  def main do
    n =
      IO.read(:line)
      |> String.trim()
      |> String.to_integer()

    IO.read(:line)
    |> String.trim()
    |> String.to_integer()
    |> (&(1..&1)).()
    |> Enum.map(fn _ ->
      IO.read(:line)
      |> String.split()
      |> Enum.map(&String.to_integer/1)
    end)
    |> solve(n)
    |> IO.puts()
  end

  defp solve(pq, n) do
    cond do
      Enum.empty?(pq) ->
        n

      true ->
        [p, q] = hd(pq)

        Enum.slice(pq, 1..-1)
        |> solve(
          cond do
            p == n -> q
            q == n -> p
            true -> n
          end
        )
    end
  end
end