import Control.Applicative ((<$>))

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

solve :: [Int] -> Int
solve xs = sum $ zipWith f xs (pyramid xs)
  where pyramid xs = [1..h] ++ [h-1, h-2..1] ++ repeat 0
          where h = floor . sqrt . fromIntegral . sum $ xs
        f x y | x >= y = x - y
              | otherwise = 0