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.Applicative
import Data.List

readInts :: IO [Int]
readInts = map read . words <$> getLine

getLines :: IO [[Int]]
getLines = do
  xs@[a, b] <- readInts
  if a == 0 && b == 0
     then return []
     else do
       rest <- getLines
       return (xs : rest)

calc :: Int -> Int -> Int
calc n x = length [1 | i <- [1..n], j <- [i+1..n], k <- [j+1..n],
                   i + j + k == x]

main :: IO ()
main = do
  xs <- getLines
  putStrLn $ intercalate "\n" [show $ calc n x | [n, x] <- xs]