fun readStr () =
    let
        fun scan reader stream = SOME (StringCvt.splitl (not o Char.isSpace) reader (StringCvt.skipWS reader stream))
    in
        valOf (TextIO.scanStream scan TextIO.stdIn)
    end


val () =
    let
        val abcString = readStr ()
        val abc = List.map (fn c =>
                                     valOf (Int.fromString (Char.toString c)))
                                 (String.explode abcString)
        val max = List.foldl
                      (fn (n, acc) => Int.max(n, acc)) (List.hd abc) abc
        val min = List.foldl
                      (fn (n, acc) => Int.min(n, acc)) (List.hd abc) abc
                                 
        val ans = max - min
    in
        print (Int.toString ans ^ "\n")
    end