import Control.Applicative ((<$>))
import Data.Char (isDigit, digitToInt)
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

main :: IO ()
main = do
  solve <$> B.getLine >>= print

solve :: ByteString -> Int
solve = B.foldl' f 0
  where
    f x c | isDigit c = x + digitToInt c
          | otherwise = x