main = do
	raw <- getLine
	let nums = map (\x -> read x :: Int) (words raw)
	let product = (nums !! 0) * (nums !! 1)
	let sum = (nums !! 0) + (nums !! 1)
	let diff = (nums !! 0) - (nums !! 1)
	putStrLn $ show (maximum (product:sum:diff:[]))