fun readStr () =
    valOf (TextIO.inputLine TextIO.stdIn)


val () =
    let
        val s = readStr ()

        val ans =
            (
              (List.foldl (fn (x, acc) => x + acc) 0)
              o
              (List.map (fn ch => (Char.ord ch) - Char.ord #"0"))
              o
              (List.filter (fn ch => Char.isDigit ch))
              o
              String.explode
            )
                s
    in
        print (Int.toString ans)
    end