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)

public partial class IntroductionToProgramming{
	static int TIMES = 3;	// ???????????°
	public static void Main(){
		string[] line = System.Console.ReadLine().Split(' ');
		int n = int.Parse(line[0]);
		int x = int.Parse(line[1]);

		while (!(n == 0 && x == 0))
		{
			int sum = 0;
			int counter = 0;

			System.Console.WriteLine((Count(true, 1, n, x, counter, sum) + Count(false, 1, n, x, counter, sum)).ToString());

			string[] line2 = System.Console.ReadLine().Split(' ');
			n = int.Parse(line2[0]);
			x = int.Parse(line2[1]);
		}
	}

	public static int Count(bool addFlg, int me, int n, int x, int counter, int sum)
	{
		// ??????????¶???????????????????????????´???????????????
		if (addFlg)
		{
			sum += me;
			counter++;
		}
		// ??????????????????????????°??¨?????´????????´??????????¨??????????
		if (counter == TIMES)
		{
			if (sum == x)
			{
				return 1;
			}
			else
			{
				return 0;
			}
		}
		// ??????????¨???°???????????°????¶???????????????´???????????????
		if (sum + me * (TIMES - counter) > x)
		{
			return 0;
		}
		// ?????????????????°????????´???????????????
		if (me == n)
		{
			return 0;
		}

		// ?¬???????????????????
		return Count(true, me + 1, n, x, counter, sum) + Count(false, me + 1, n, x, counter, sum);
	}
}