import Control.Applicative
import Data.List
import Data.Char (digitToInt)
import Text.Parsec (parse, char, digit)
import qualified Text.Parsec as P
import Text.Parsec.String

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

solve :: String -> Int
solve = either (const 0) id . parse expr ""

num :: Parser Int
num = do
  f <- negate <$ char '-' <|> return id
  n <- digitToInt <$> digit
  return $ f n

term :: Parser Int
term = char '(' *> expr <* char ')' <|> num

expr :: Parser Int
expr = do
  x <- term
  fs <- P.many $ do
    f <- (+) <$ char '+' <|> (-) <$ char '-'
    x <- term
    return $ flip f x
  return $ foldl' (\x f -> f x) x fs