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)

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Text;

class Program
{
	static void Main(string[] args)
	{
        List<int> n = new List<int>();
        List<int> x = new List<int>();

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

        }



        for (int i = 0; i < n.Count;i++)
        {
            int sum = 0;
            for (int j = 1; j <= n[i] - 2;j++)
            {
                for (int k = j + 1; k <= n[i] - 1;k++)
                {
                    for (int l = k + 1; l <= n[i];l++)
                    {
                        if (j + k + l == x[i]) sum++;
                    }
                }
            }

            Console.WriteLine(sum);
        }
	}
}