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)

import Control.Monad
import Control.Applicative

combinations :: Int -> [a] -> [[a]]
combinations 0 _ = [[]]
combinations _ [] = []
combinations n (x:xs) = (map (x:) (combinations (n-1) xs)) ++ (combinations n xs)

solve :: [Int] -> String
solve [n, x] =
   show $ length [nc3 | nc3<-combinations 3 [1..n], sum nc3==x]

main =
    mapM_ putStrLn =<< map solve . takeInputs . lines <$> getContents
    where
    takeInputs :: [String] -> [[Int]]
    takeInputs = takeWhile (not . all (== 0)) . map (map read . words)