nFactors :: Int -> [Int]
nFactors n = [x | x <- [1..n], n `mod` x == 0]

genNumList :: Int -> [Int]
genNumList n = [x | x <- [1..n]]

main :: IO ()
main = do
    arg1 <- getLine
    let n = read arg1 ::Int

    let a = genNumList n 
    let b = map length $ map nFactors a
    let r = sum $ zipWith (*) a b
    
    print r