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

namespace _20170409_AOJ
{
    class Program
    {
        static void Main(string[] args)
        {
            for (;;)
            {
                int[] iArr = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();
                int n = iArr[0];
                int x = iArr[1];

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

                int count = 0;
                int li = Math.Max(1, x - (2 * n - 1));
                int ui = Math.Min(x / 3, n - 1);
                for (int i = li; i < ui; i++)
                {
                    int lj = Math.Max(i + 1, x - i - n);
                    int uj = Math.Min((x - i - 1) / 2, n);

                    count += uj - lj + 1;
                }

                Console.WriteLine(count);
            }

            Console.ReadLine();
        }
    }
}