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 AizuOnlineJudge
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] arr;
            while (IsInput(out arr))
            {
                var n = arr[0]; //1 ～ nまで
                var x = arr[1]; //合計(target)

                var c = 0;

                for(var i = n; i >= 3; --i)
                {
                    for(var k = i - 1; k >= 2; --k)
                    {
                        var m = x - i - k;
                        if (m >= k) break;
                        if (m < 1) continue;
                        c++;
                    }
                }
                Console.WriteLine(c);
            }
        }

        private static bool IsInput(out int[] arr)
        {
            var s = Console.ReadLine();
            if (s == "0 0") { arr = null; return false; }

            arr = s.Split(' ').Select(int.Parse).ToArray();
            return true;
        }
    }
}