Problem:
How many ways?

Write a program which identifies the number of combinations of three integers which satisfy the following conditions:

You should select three distinct integers from 1 to n.

A total sum of the three integers is x.

For example, there are two combinations for n = 5 and x = 9.

1 + 3 + 5 = 9

2 + 3 + 4 = 9

Input

The input consists of multiple datasets. For each dataset, two integers n and x are given in a line.

The input ends with two zeros for n and x respectively. Your program should not process for these terminal symbols.

Constraints

3 ≤ n ≤ 100

0 ≤ x ≤ 300

Output

For each dataset, print the number of combinations in a line.

Sample Input

5 9
0 0

Sample Output

2

Note

      解説

Solution in Haskell (judge verdict: Accepted)

combinations' :: Int -> [a] -> [[a]]
combinations' n xs = comb n xs [] [] where
  comb 0 _      ys zs = reverse ys : zs
  comb _ []     _  zs = zs
  comb n (x:xs) ys zs = comb (n - 1) xs (x:ys) (comb n xs ys zs)

solve :: [Int] -> Int
solve [n,x] = length $ filter ((== x) . sum) $ combinations' 3 [1..n]
solve _ = undefined

main :: IO ()
main  = getContents
    >>= return . takeWhile (/= [0,0]) . map (map read) . map words . lines
    >>= return . map solve
    >>= mapM_ print