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.Linq;

namespace AOJ_Practice
{
    class Program
    {
        static void Main(string[] args)
        {
            int combinationCount = 0;
            while (true)
            {
                var oneLine = Console.ReadLine().Split(' ').Select(int.Parse).ToList();

                if (oneLine.All(x => x == 0))
                {
                    goto Finish;
                }

                var n = oneLine[0];
                var sum = oneLine[1];

                for (int i = 1; i <= n; i++)
                {
                    //if (3 * (i + 1) == sum)
                    //{
                    //    combinationCount++;
                    //}
                    for (int j = i + 1; j <= n; j++)
                    {
                        for (int k = j + 1; k <= n; k++)
                        {
                            if (i + j + k == sum)
                            {
                                combinationCount++;
                            }
                        }
                    }
                }
                Console.WriteLine(combinationCount);
                combinationCount = 0;
            }

            Finish:
            return;
        }
    }
}