import Data.List.Split

main :: IO ()
main = do
    getLine
    a <- map parse . lines <$> getContents
    let (i, p) = (sum $ map fst a, sum $ map snd a)
    putStrLn $ showWithPoint(10^10 * i + p)

parse :: String -> (Integer, Integer)
parse = zipInt . splitWhen (== '.')

zipInt :: [String] -> (Integer, Integer)
zipInt [a, b]
    | head a /= '-' = (read a, readPoint b)
    | otherwise = (read a, -readPoint b)
zipInt [a] = (read a, 0)

readPoint :: String -> Integer
readPoint = read . take 10 . (++ repeat '0')

showWithPoint :: Integer -> String
showWithPoint x
    | x < 0 = '-':showWithPoint (-x)
    | otherwise = (show (x `div` 10 ^ 10)) ++ "." ++ (show10 10 (x `mod` 10^10))

show10 :: Integer -> Integer -> String
show10 0 _ = ""
show10 d x = (show $ x `div` 10^(d-1)) ++ show10 (d - 1) (x `mod` 10^(d-1))