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: Wrong Answer)

using System;
using System.Collections.Generic;

class A{
	public static void Main(){


		while (true) {
			
			string[] s = Console.ReadLine ().Split (' ');
			int n = int.Parse(s [0]);
			int x = int.Parse(s [1]);

			int max = n;
			int count = 0;

			if (n == x && n == 0) {
				break;
			}

			for (int i=1; i <= (n/2); i++) {
				if ((x - max - i) < n) {
					count++;
				}
				max--;			}
			Console.WriteLine (count);
		}



	}
}