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)

from sys import stdin

def main():
    for l in stdin:
        n, x = map(int, l.split(' '))
        if 0 == n == x:
            break

        print(len(num_sets(n, x)))

def num_sets(n, x):
    num_sets = []

    for i in range(1, n-1):
        for j in [m for m in range(i+1, n)]:
            k = x - (i+j)

            if n < k:
                continue

            if k <= j:
                break

            num_sets.append((i, j, k))

    return num_sets

if __name__ == '__main__': main()