import Control.Applicative ((<$>))

main :: IO ()
main = do
  solve <$> readLn >>= print

solve :: Int -> Int
solve n = f 0 0 n
  where
    f mv av cv
      | cv == 0 = mv - av
      | otherwise = f (max mv (av + cv * 2)) (av + cv) (cv `div` 2)