fun readStrWithoutWS () =
    let
        val sOption = TextIO.inputLine TextIO.stdIn
    in
        case sOption of
            NONE => ""
          | SOME s => 
            String.implode
                (List.filter
                     (fn c => Char.isAlphaNum c)
                     (String.explode s))
    end

val () =
    let
        val s = readStrWithoutWS ()
        val ans =
            if String.size s = 0 then 1
            else
                (
                  List.foldl
                      (fn (ch, acc) => if ch = #"L" then acc * 2 else acc * 2 + 1)
                      1
                      (String.explode s)
                )
    in
        print (Int.toString ans ^ "\n")
    end