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: Accepted)

#include <stdio.h>
int main(void){
	int n, x, a, i, j, k;
	while(1){
		x = 0;
		scanf("%d %d", &n, &a);
		if(n == 0 && a == 0)break;
		for(i = 1; i <= n; i++){
			for(j = 1; j <= i; j++){
				for(k = 1; k <= i+j; k++){
					if(i+j+k == a && i > j && j > k){
						x++;
					}
				}
			}
		}
		printf("%d\n", x);
	}
	
	return 0;
}