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 ITP1_7_B
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int> map = new List<int>(161700);

            string[] input;
            int num;
            int total;

            while (!(input = Console.ReadLine().Split(' ')).All( s => s == "0"))
            {
                map.Clear();
                num = Convert.ToInt32(input[0]);
                total = Convert.ToInt32(input[1]);

                for (int i = num; i > 0; i--)
                {
                    for (int j = i - 1; j > 0; j--)
                    {
                        int sum1 = i + j;
                        for (int k = j - 1; k > 0; k--)
                        {
                            map.Add(sum1 + k);
                        }

                    }
                }

                Console.WriteLine(map.Count(i => i == total));
            }
        }
    }
}