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 ConsoleApp_ITP1_7_B
{
    class Program
    {
        static void Main(string[] args)
        {
            for (; ; )
            {
                int[] input = Console.ReadLine().Split(' ').Select(s => int.Parse(s)).ToArray();
                var n = input[0];
                var x = input[1];

                if(n == 0 && x == 0)
                {
                    break;
                }
                else
                {
                    int counter = 0;

                    for (int i = 1; i <= n; i++)
                    {
                        for (int j = 1; j <= n; j++)
                        {
                            if (i == j)
                            {
                                continue;
                            }
                            else
                            {
                                for (int k = 1; k <= n; k++)
                                {
                                    if (i == k || j == k)
                                    {
                                        continue;
                                    }
                                    else
                                    {
                                        if (i + j + k == x)
                                        {
                                            counter += 1;
                                        }
                                    }
                                }
                            }
                        }
                    }
                    Console.WriteLine(counter/6);
                }
            }
        }
    }
}