import Control.Applicative ((<$>), (<*>))
import Data.List

import Data.Char (isSpace)
import Data.ByteString.Char8 (ByteString)
import qualified Data.ByteString.Char8 as B

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

solve :: [Int] -> Int -> Int
solve as v = sum as - v

readIntList :: IO [Int]
readIntList = unfoldr f <$> B.getLine
  where
    f s = do
      (n, s') <- B.readInt s
      return (n, B.dropWhile isSpace s')