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;
namespace csharptest
{
    class Program
    {
        static void Main(string[] args)
        {
            int count;
            int[] ans = new int[1000];
            string[] str = Console.ReadLine().Split(' ');
            for (count = 0; str[0] != "0" && str[1] != "0"; count++)
            {
                ans[count] = 0;
                int n = int.Parse(str[0]);
                int x = int.Parse(str[1]);
                for (int i = 1; i < n-1; i++)
                {
                    for (int s = i + 1; s < n; s++)
                    {
                        for (int t = s + 1; t <= n; t++)
                        {
                            if (i + s + t == x)
                            {
                                ans[count]++;
                            }
                        }
                    }
                }
                str = Console.ReadLine().Split(' ');
            }
            for (int n = 0; n < count; n++)
                Console.WriteLine(ans[n]);
        }
    }
}