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.IO;
using System.Linq;
using System.Collections.Generic;

public class Program
{

	public void Proc()
	{
        System.Text.StringBuilder ans = new System.Text.StringBuilder();
        while(true) {
            int[] inpt = Reader.ReadLine().Split(' ').Select(a => int.Parse(a)).ToArray();
            if(inpt.All(a=>a==0)) {
                break;
            }
            ans.AppendLine(GetAns(inpt[0], inpt[1]).ToString());
        }
        Console.Write(ans.ToString());
    }

    private int GetAns(int n, int x) {
        int ans = 0;
        for (int i = 1; i <= n - 1; i++) {
            for (int j = i + 1; j <= n; j++) {
                int diff = x - (i + j);
                if (diff <= j) {
                    break;
                }
                if (diff > n) {
                    continue;
                }
                ans++;
            }
        }
        return ans;
    }

    public class Reader
	{
		private static StringReader sr;
		public static bool IsDebug = false;
		public static string ReadLine()
		{
			if (IsDebug)
			{
				if (sr == null)
				{
					sr = new StringReader(InputText.Trim());
				}
				return sr.ReadLine();
			}
			else
			{
				return Console.ReadLine();
			}
		}
		private static string InputText = @"


5 9
0 0


";
	}

	public static void Main(string[] args)
	{
#if DEBUG
		Reader.IsDebug = true;
#endif
		Program prg = new Program();
		prg.Proc();
	}
}