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;
using System.Collections.Generic;

namespace ConsoleApp3
{
    class Program
    {
        static void Main(string[] args)
        {
            List<int[]> numbers = new List<int[]>();
            while (true)
            {
                int[] data = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
                if (data[0] == 0 && data[1] == 0) break;                    
                else numbers.Add(data);
            }

            int[] comb = new int[numbers.Count];
            for (int i = 0; i < numbers.Count; i++)
            {
                int n = numbers[i][0];
                int x = numbers[i][1];
                int x1, x2, x3;
                for (int k = 0; k < n-2; k++)
                {
                    x1 = k + 1;
                    for (int l = 0; l < n-1; l++)
                    {
                        x2 = x1 + l + 1;
                        x3 = x - (x1 + x2);
                        if (x2 < x3 && x3 <= n)
                        {
                            comb[i] += 1;
                        }
                    }
                }
            }
            foreach(int item in comb)
            Console.WriteLine(item);

        }
    }
}