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.Collections.Generic;

namespace ITP1_7_B
{
	class Program
	{
		static void Main(string[] args)
		{
			List<Tuple<int, int>> ts = new List<Tuple<int, int>>();

			// 入力
			Input(ts);

			// 出力
			Output(ts);
		}

		static void Input(List<Tuple<int, int>> ts)
		{
			while(true) {
				string[] vs = Console.ReadLine().Split(' ');
				int n = int.Parse(vs[0]);
				int x = int.Parse(vs[1]);

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

				ts.Add(Tuple.Create(n, x));
			}
		}

		static void Output(List<Tuple<int, int>> ts)
		{
			foreach(Tuple<int, int> t in ts) {
				int cnt = 0;

				for(int i = 1; i <= t.Item1; i++) {
					for(int j = i + 1; j <= t.Item1; j++) {
						for(int k = j + 1; k <= t.Item1; k++) {
							if(k == i || k == j) {
								continue;
							}

							if(i + j + k == t.Item2) {
								cnt++;
							}
						}
					}
				}

				Console.WriteLine(cnt);
			}
		}
	}
}