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.Text;

namespace AOJ
{
    class Program
    {
        static void Main(string[] args)
        {
            for (; ; )
            {
                var inputLine = Console.In.ReadLine();
                var inputs = inputLine.Split(new char[] { ' ', '\t', '　' });
                if (inputs.Length != 2)
                {
                    return;
                }

                var n = int.Parse(inputs[0]);
                var x = int.Parse(inputs[1]);
                if (n == 0 && x == 0)
                {
                    break;
                }

                int wayCount = 0;

                for (int i0 = 1; i0 <= n; ++i0)
                {
                    var remain0 = x - i0;   // よく読めばいらない
                    if (remain0 <= 0) break;

                    for (int i1 = i0 + 1; i1 <= n; ++i1)
                    {
                        var remain1 = remain0 - i1;
                        if (remain1 <= 0) break;

                        for (int i2 = i1 + 1; i2 <= n; ++i2)
                        {
                            var remain2 = remain1 - i2;
                            if (remain2 < 0) break;    // よく読めばいらない

                            if (remain2 == 0)
                            {
                                ++wayCount;
                            }
                        }
                    }
                }

                Console.WriteLine(wayCount);
            }
        }
    }
}