import Control.Applicative ((<$), (<|>))
import Control.Monad.State
import Data.List
import Data.Char (digitToInt, isDigit)

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

solve :: String -> Int
solve = maybe 0 id . parse expr

type Parser = StateT String Maybe

parse :: Parser a -> String -> Maybe a
parse = evalStateT

anyChar :: Parser Char
anyChar = do
  s <- get
  case s of
   (x:xs) -> do
     put xs
     return x
   [] -> lift Nothing

satisfy :: (Char -> Bool) -> Parser Char
satisfy f = do
  c <- anyChar
  if f c then return c
    else lift Nothing

char c = satisfy (== c)
digit = satisfy isDigit

many :: Parser a -> Parser [a]
many p = (:) <$> p <*> many p <|> return []

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 <- many $ do
    f <- (+) <$ char '+' <|> (-) <$ char '-'
    x <- term
    return $ flip f x
  return $ foldl' (\x f -> f x) x fs