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 ITP1_7_B
{
    class Program
    {
        static void Main(string[] args)
        {
            //1からnまでの数の中から重複なしで3つを選び、それらの合計がxとなる組み合わせの数を求める
            //n,xがともに0：入力終了
            ////////////////////////////////////////////////////////////////////////////////////////

            while (true)
            {
                int count = 0;                  //組み合わせの数をカウントする変数
                string[] str = Console.ReadLine().Split(' ');
                int n = int.Parse(str[0]);
                int x = int.Parse(str[1]);

                int a;
                int b;
                int c;

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

                else
                {
                    for (a = 1; a <= n; a++)
                    {
                        for (b = a + 1; b <= n; b++)
                        {
                            for (c = b + 1; c <= n; c++)
                            {
                                if (a != b && b != c && c != a && a + b + c == x)
                                {
                                    count++;
                                }
                            }
                        }
                    }

                }
                Console.WriteLine((count).ToString());
            }

        }
    }
}