main :: IO ()
main = interact $ show . solve . map read . words

myFloor :: Int -> Int -> Int
myFloor m n = floor $ (fromIntegral m) / (fromIntegral n)

solve :: [Int] -> Int
solve [works, deadline] = yaruki_memo !! deadline
    where
        yaruki_memo :: [Int]
        yaruki_memo = map yaruki [0..]
        
        works_memo :: [Int]
        works_memo = map work [0..]
        
        work :: Int -> Int
        work 0 = works
        work x = work (x - 1) - yaruki (x - 1)
        
        yaruki :: Int -> Int
        yaruki 0 = 0
        yaruki x = myFloor (works_memo !! (x - 1) - yaruki_memo !! (x - 1)) ((deadline - x + 1) ^ 2)