module Main where

-- (1+n) * n / 2 + kn = A
-- A - (1+n) * n / 2 = nの倍数

main :: IO ()
main = readLn >>= putStrLn . solve

solve :: Int -> String
solve = judge . go 3
  where
  go i a | calc i a `mod` i == 0 = True
         | (1+i) * i `div` 2 > a = False
         | otherwise             = go (succ i) a

calc :: Int -> Int -> Int
calc x y = y - (1+x) * x `div` 2

judge :: Bool -> String
judge True  = "YES"
judge False = "NO"