import Data.List

isprime :: Integer -> Bool
isprime 1 = False
isprime 2 = True
isprime n =
	if n `mod` 2 == 0
		then False
		else and [n `mod` i /= 0|i<-[3,5..sq]]
	where sq = ceiling (sqrt (fromIntegral n))

primefact' :: Integer -> Integer -> [Integer]
primefact' 1 _ = [1]
primefact' n p =
	if n `mod` p == 0
		then if isprime (n `div` p)
			then p : [(n `div` p)]
			else p : primefact' (n `div` p) p
		else primefact' n (p + 1)

primefact :: Integer -> [Integer]
primefact n =
	if isprime n
		then [n]
		else primefact' n 2

main = do
	n <- readLn
	let p = if n `mod` 2 == 1 then n else n `div` 2
	print $ (product . map (sum . nub . scanl1 (*) . (1:)) . group . primefact) p