import Data.List (group)


primes =
    let
        f (p : ps) = p : (filter $ (/= 0) . (`mod` p)) ps
    in
        f [ 2 .. ]

primeFactors n = [ x | x <- takeWhile (\y -> y * y <= n) primes, n `mod` x == 0 ]

factorize 1 = []
factorize n =
    let
        x = case primeFactors n of
            []     -> n
            p : ps -> p
    in
        x : factorize (n `div` x)

toInt :: String -> Int
toInt = read

factors :: Int -> Int
factors = product . map ((+1) . length) . group . factorize

main = do
    n <- toInt <$> getLine

    print . sum . map factors $ [ 1 .. (n - 1) ]
