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 Python (judge verdict: Accepted)

def get_num(n, x):
    ans = 0
    for n3 in xrange(min(n, x - 2), (x + 2) / 3, -1):
        for n2 in xrange(min(n3 - 1, x - n3 - 1), (x - n3 + 1) / 2 - 1, -1):
            for n1 in xrange(min(n2 - 1, x - n3 - n2), 0, -1):
                if n3 == x - n1 - n2:
                    ans += 1
                    break
    return ans


while True:
    [n, x] = [int(m) for m in raw_input().split()]
    if [n, x] == [0, 0]:
        break
    if x < 3:
        print(0)
    else:
        print(get_num(n, x))