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;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {

            //入力読取。
            List<int> combList = new List<int>();
            string strBreak = "0 0";
            while (true)
            {
                string strMaxAndSum = Console.ReadLine();
                if (strMaxAndSum == strBreak)
                {
                    break;
                }
                Calculation insC = new Calculation(strMaxAndSum);
                combList.Add(insC.GetComb());
            }

            //出力
            foreach (int comb in combList)
            {
                Console.WriteLine(comb);
            }

            Console.ReadKey();
        }
    }

    class Calculation
    {
        private string strMaxAndSum;
        private int intComb;

        public Calculation(string strMaxAndSum)
        {
            this.strMaxAndSum = strMaxAndSum;
            CombCount();
        }

        private void CombCount()
        {
            string[] strMaxSumArr = strMaxAndSum.Split(' ');
            int intMax = int.Parse(strMaxSumArr[0]);
            int intWantSum = int.Parse(strMaxSumArr[1]);
            for (int firstNum = 1; firstNum < intMax - 1; firstNum++)
            {
                for (int secondNum = firstNum + 1; secondNum < intMax; secondNum++)
                {
                    for (int thirdNum = secondNum + 1; thirdNum <= intMax; thirdNum++)
                    {
                        int intSum = firstNum + secondNum + thirdNum;
                        if (intWantSum == intSum)
                        {
                            intComb++;
                        }
                        intSum = 0;
                    }
                }
            }
        }

        public int GetComb()
        {
            return intComb;
        }

    }


}