fun readInt () =
    valOf (TextIO.scanStream (Int.scan StringCvt.DEC) TextIO.stdIn)

                           
fun findAns n pqs =
    let
        val cups = Array.array (4, 0)
    in
        (
          Array.update (cups, n, 1);
          List.app
              (fn (p, q) =>
                  let
                      val temp = Array.sub (cups, p)
                  in
                      (
                        Array.update (cups, p, Array.sub (cups, q));
                        Array.update (cups, q, temp)
                      )
                  end
              )
              pqs;
          #1 (valOf (Array.findi (fn (_, x) => x = 1) cups))
        )
    end

        
val () =
    let
        val n = readInt ()
        val m = readInt ()
        val pqs = List.tabulate (m, fn _ => (readInt (), readInt ()))

        val ans = findAns n pqs
    in
        print (Int.toString ans ^ "\n")
    end