import Control.Monad
import Control.Applicative
import Data.List
import Data.Ord

main :: IO ()
main = do
  c <- getLine
  putStrLn $ show (solve 1 c)

solve :: Int -> [Char] -> Int
solve n "" = n
solve n (x:xs)
  | x == 'L' = solve (n*2) xs
  | otherwise = solve (n*2+1) xs