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


val () =
    let
        val y = readInt ()
        val n = readInt ()
        val a_s = List.tabulate (n, fn _ => readInt ())

        val sum = List.foldl (fn (a, acc) =>
                                 a + acc)
                             0
                             a_s

        val ans = if sum <= y then Int.toString (y - sum)
                  else "red"
    in
        print (ans ^ "\n")
    end