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.Globalization;
using System.IO;
using System.Linq;
using System.Text;

namespace LogicSummoner
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                var nums = GetNumbersInt();
                var n = nums[0];
                var x = nums[1];
                if (n == 0 && x == 0)
                {
                    break;
                }

                var count = 0;

                // 1-3
                for (int i = 1; i < n - 1; i++)
                {
                    // 2-4
                    for (int j = i + 1; j < n; j++)
                    {
                        var k = x - i - j;
                        if (j < k && k < n + 1)
                        {
                            count++;
                        }
                    }
                }

                System.Console.WriteLine(count);
            }
        }

        //static StreamReader Console = new StreamReader("input.txt");

        static int GetNumber()
        {
            return int.Parse(Console.ReadLine().Trim());
        }

        static double GetDounble()
        {
            return double.Parse(Console.ReadLine().Trim());
        }

        static int[] GetNumbersInt(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => int.Parse(x)).ToArray();
        }

        static long[] GetNumbersLong(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => long.Parse(x)).ToArray();
        }

        static double[] GetNumbersDouble(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).Select(x => double.Parse(x)).ToArray();
        }

        static string[] GetStrings(int n = 0)
        {
            return Console.ReadLine().Trim().Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries).ToArray();
        }
    }
}