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;
class Program
{
    static void Main(string[] args)
    {
        while (true)
        {
            string[] data = Console.ReadLine().Split(' ');
            int n = int.Parse(data[0]);
            int m = int.Parse(data[1]);
            if (n == 0 && m == 0) break;

            int count = 0;
            for (int i = 1,icount = n-2; i <= icount; i++)
            {
                for (int j = i + 1,jcount = n-1; j <= jcount; j++)
                {
                    for (int k = j + 1; k <= n; k++)
                    {
                        if (i + j + k == m)
                        {
                            count++;
                        }
                    }
                }
            }
            Console.WriteLine(count);
        }
    }
}