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 ITP1_7_B
{
    class Program
    {
        static void Main(string[] args)
        {
            while (true)
            {
                string[] input = Console.ReadLine().Split(' ');
                int n = int.Parse(input[0]);
                int x = int.Parse(input[1]);
                if (n == 0)
                    break;
                Console.WriteLine(CountCombi(n, x));
            }
        }

        static int CountCombi(int n,int x)
        {
            int ret = 0;
            for(int i = 1; i < n - 1; i++)
            {
                for(int j = i + 1; j < n; j++)
                {
                    int temp = x - (i + j);
                    if (j < temp && temp <= n)
                        ret++;
                }
            }
            return ret;
        }
    }
}