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


val () =
    let
        val s_s = List.tabulate (6, fn _ => readInt ())
        val (sum, min, max) =
            List.foldl
                (fn (s, (sumAcc, minAcc, maxAcc)) =>
                    (sumAcc + s, Int.min (s, minAcc), Int.max (s, maxAcc)))
                (0, 100, 0)
                s_s
        val ans = Real.fromInt (sum - min - max) / 4.0
    in
        print ((Real.fmt (StringCvt.FIX (SOME 2)) ans) ^ "\n")
    end