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;

namespace C_sharp
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                var line = Console.ReadLine().Split(' ');
                var n = int.Parse(line[0]);
                var x = int.Parse(line[1]);

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

                var lower1 = x / 3 + 1;
                var upper1 = (x - 3 < n) ? x - 3 : n;
                var cnt = 0;
                for (var n1 = lower1; n1 <= upper1; n1++)
                {
                    var rest = x - n1;
                    var lower2 = rest / 2 + 1;
                    var upper2 = (n1 - 1 < rest - 1) ? n1 - 1 : rest - 1;
                    cnt += upper2 - lower2 + 1;
                }

                Console.WriteLine(cnt);
            }
        }
    }
}