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 C++ (judge verdict: Time Limit Exceeded)

#include <cstdio>
using namespace std;

int count;
int n;

void dfs(int a, int b, int k)
{
	int i;

	if (a==0 && b==0){
		count++;
		return ;
	}
	for (i=k; i<=n; i++)
		dfs(a-1, b-i, i+1);

}

int main (void)
{
	int x, j, i;

	while (scanf("%d %d", &n, &x)!=EOF && n!=0 || x!=0){
		dfs(3, x, 1);
		printf("%d\n", count);
	}

	return 0;
}