import Data.Maybe
import Data.List
import Data.Char
import Control.Monad

main = getLine >>= print . tsutsu

tsutsu = fromJust . maximum . map eval . enumerate

enumerate xs = map (take l) . take l . tails . cycle $ xs
 where l = length xs

eval s = do
 guard (isDigit (head s) && isDigit (last s))
 return $ sum (unfoldr parse s)

parse "" = Nothing
parse ('+':s) = parse s
parse ('-':s) = let (n,s') = span isDigit s in Just (negate (read n), s')
parse s = let (n,s') = span isDigit s in Just (read n, s')