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)

//ITP1_7_B
//????????????  45???

using System;
using System.Collections.Generic;

class ITP1_7_B
{
    static void Main(string[] args)
    {

        int count = 0;
        int[] result = new int[100];

        while (true)
        {
            int[] st = Array.ConvertAll<string, int>((Console.ReadLine().Split(' ')), delegate (string value)
            {
                return int.Parse(value);
            });

            if (st[0] == 0 && st[1] == 0)
                break;
            else
                result[count++] = judge(st[0], st[1]);

        }

        for (int i = 0; i < count; i++)
            Console.WriteLine(result[i]);

    }

    private static int judge(int n, int x)
    {
        int ans = 0;

        for(int i = 1;i <= n; i++)
        {
            for(int j = i + 1;j <= n; j++)
            {
                for(int k = j + 1;k <= n; k++)
                {
                    if (x == k + j + i)
                        ans++;
                }
            }    
        }

        return ans;
    }
}