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: Wrong Answer)

using System;

namespace ITP1_7_B
{
    class Program
    {
        static void Main(string[] args)
        {
            int n, x, count ;
            while(true)
            {
                string[] str = Console.ReadLine().Split(' ');
                n = int.Parse(str[0]);
                x = int.Parse(str[1]);
                if (n == 0 && x == 0)
                    break;
                count = 0;
                for (int i = 1; i <= min(n - 2, x / 3 - 1); i++) 
                {
                    for (int j = i + 1; j <= min(n - 1, x - i - 1); j++) 
                    {
                        if (x <= (i + j + n))
                            count += 1;
                    }

                }
                Console.WriteLine("{0}", count);
            }
        }

        static int min(int a, int b)
        {
            if (a < b)
                return a;
            else
                return b;
        }
    }
}