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;
using System.Collections.Generic;

namespace Algorithm
{
    class Program
    {
        static void Main(string[] args)
        {
            var rList = new List<int>();

            while (true)
            {
                var line = Console.ReadLine().Split().Select(s => int.Parse(s)).ToArray();

                if (!IsLoop(line)) break;

                rList.Add(Calc(line));
            }

            Output(rList);

        }

        static bool IsLoop(int[] line)
        {
            if (line.Any(a => a != 0))
                return true;
            return false;
        }

        static int Calc(int[] line)
        {
            var n = line[0];
            var x = line[1];
            var count = 0;

            foreach (var i in Enumerable.Range(1, n-2))
            {
                foreach (var j in Enumerable.Range(i+1, n-i-1))
                {
                    foreach (var k in Enumerable.Range(j+1, n-j))
                    {
                        if (i + j + k == x)
                        {
                            count++;
                        }
                    }
                }
            }
            return count;

        }

        static void Output(List<int> result)
        {
            foreach (var r in result)
            {
                Console.WriteLine(r);
            }
        }
    }

}