import Control.Applicative ((<$>))
import qualified Data.ByteString.Char8 as C
import Data.Maybe (fromJust)

unsafeReadInt :: C.ByteString -> Int
unsafeReadInt = fst . fromJust . C.readInt

main :: IO ()
main = do
    _ <- C.getLine
    xs <- map unsafeReadInt . C.words <$> C.getLine
    v <- unsafeReadInt <$> C.getLine
    print $ sum xs - v