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: Wrong Answer)

using System;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {

            int x = 0;
            while (true)
            {
                string[] s = Console.ReadLine().Split(' ');
                int n = int.Parse(s[0]);
                int b = int.Parse(s[1]);
                int[] a = new int[n];
                if(n == 0 && b == 0)
                {
                    break;
                }
                for (int i = 1; i <= n; i++) 
                {
                    a[i-1] = i;
                }
                for(int i = 1; i < n; i++)
                {
                    for(int j = 1;j < n; j++)
                    {
                        for(int k = 1;k < n; k++)
                        {
                            if(i + j + k == b){
                                x++;
                            }
                        }
                    }
                }
            }
            Console.WriteLine(x);
        }
    }
}