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.Linq;

namespace atcoder
{
    class Program
    {
        static void Main(string[] args)
        {
            // ITP1_7_B
            while (true) {
                var input = Console.ReadLine().Split(' ');
                if (input.Length != 2) break;
                
                if (!ITP1_7_B(input)) break;
            }
        }

        static bool ITP1_7_B(string[] input)
        {
            var n = int.Parse(input[0]);
            var x = int.Parse(input[1]);
            if (n == 0 && x == 0) return false;

            var count = 0;
            for (var i = 1; i <= n - 2; ++i) {
                for (var j = i + 1; j <= n - 1; ++j) {
                    for (var k = j + 1; k <= n; ++k) {
                        if (i + j + k == x) {
                            count++;
                        }
                    }
                }
            }

            Console.WriteLine(count);
            return true;
        }
    }
}