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;

    class Program
    {
        static void Main()
        {
            while (true)
            {
                int[] num = TypeConverter.arrayStrToInt(Console.ReadLine().Split(' '));

                if (num[0] == 0 && num[1] == 0)
                    break;

                int res = 0;
                for (int x1 = 1; x1 <= num[0]; x1++)
                {
                    for (int x2 = x1 + 1; x2 <= num[0]; x2++)
                    {
                        for (int x3 = x2 + 1; x3 <= num[0]; x3++)
                        {
                            if (x1 + x2 + x3 == num[1])
                                res++;
                        }
                    }
                }

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

class TypeConverter
    {
        static public int[] arrayStrToInt(string[] str)
        {
            return Array.ConvertAll<string, int>(str,
                delegate(string value)
                {
                    return int.Parse(value);
                }
            );
        }

        static public string[] arrayIntToStr(int[] x)
        {
            return Array.ConvertAll<int, string>(x,
                delegate(int value)
                {
                    return value.ToString();
                }
            );
        }
    }