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 Python3 (judge verdict: Accepted)

import sys

for line in sys.stdin:
    n,x = map(int,line.split())
    if n==0 and x==0:
        break
    _range = list(range(1,n+1))
    conb = []
    for i in _range[::-1]:
        d = x - i
        if i - 1 <= 0:
            continue
        for j in _range[:i-1][::-1]:
            d2 = d - j
            if j - 1 <= 0:
                continue
            for k in _range[:j-1][::-1]:
                if d2 - k == 0:
                    conb.append((i,j,k))

    print(len(conb))