import Control.Applicative
import qualified Data.List as Li
import Control.Monad(unless,forM_,replicateM)
import qualified Data.ByteString.Char8         as BS
import qualified Data.Array as A
import qualified Data.Array.IO as AI
import qualified Data.Text as T
import qualified Data.Text.IO as T
import qualified Data.Char as Ch
import qualified Data.Vector as V

g=map (read . BS.unpack) . BS.words <$> BS.getLine ::IO[Int]

main = do
    s <-BS.unpack<$>BS.getLine
    let k=map read$words$Li.intersperse ' 's
    print$sum k