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)

module Main where

import Control.Applicative
import Numeric

main :: IO ()
main = loop

loop :: IO ()
loop = do
  { [n, x] <- getInts
  ; if n == 0 && x == 0 then return ()
    else print (length (filter ((x ==) . sum) (comb [1 .. n] 3))) >> loop
  }

comb :: [Int] -> Int -> [[Int]]
comb ns 0 = [[]]
comb ns k = if length ns == k then [ns]
            else map (head ns :) (comb (tail ns) (k - 1)) ++ comb (tail ns) k
--
getInts :: IO [Int]
getInts = map read . words <$> getLine

putInts :: [Int] -> IO ()
putInts = putStrLn . unwords . map show

getDoubles :: IO [Double]
getDoubles = map read . words <$> getLine

putDoubles :: [Double] -> IO ()
putDoubles = putStrLn . unwords . map showDouble

showDouble :: Double -> String
showDouble d = showFFloat Nothing d ""