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;

public class Program
{
	public static void Main(string[] args)
	{
		var ss = new StreamScanner();
		//---------------------------------
		//????????????int, double, string?????????????????£????????????
		while (true)
		{
			var n = ss.Next<int>();
			var x = ss.Next<int>();
			if (n == 0 && x == 0)
			{
				break;
			}

			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 (i + j + k == x)
						{
							ans += 1;
						}
					}
				}

			}
			Console.WriteLine(ans);

			//int x = ss.Next<int>();
			//double d = ss.Next<double>();
			//string s = ss.Next<string>();

			//?????°???????????????????????¨?????????????????????????????????????????????????´???????
			//int[] array = ss.Next<int>(10);
			//---------------------------------
		}
	}
}
public class StreamScanner
{
	private readonly char[] _c = { ' ' };
	private int _index = -1;
	private string[] _input = new string[0];
	private readonly System.IO.StreamReader _sr = new System.IO.StreamReader(Console.OpenStandardInput());

	public T Next<T>()
	{
		if (_index == _input.Length - 1)
		{
			_index = -1;
			while (true)
			{
				string rl = _sr.ReadLine();
				if (rl == null)
				{
					if (typeof(T).IsClass) return default(T);
					return (T)typeof(T).GetField("MinValue").GetValue(null);
				}
				if (rl != "")
				{
					_input = rl.Split(_c, StringSplitOptions.RemoveEmptyEntries);
					break;
				}
			}
		}
		return (T)Convert.ChangeType(_input[++_index], typeof(T), System.Globalization.CultureInfo.InvariantCulture);
	}

	public T[] Next<T>(int x)
	{
		var ret = new T[x];
		for (var i = 0; i < x; ++i) ret[i] = Next<T>();
		return ret;
	}

	public T[][] Next<T>(int x, int y)
	{
		var ret = new T[y][];
		for (var i = 0; i < y; ++i) ret[i] = Next<T>(x);
		return ret;
	}
}