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 競プロ_Csharp {
    class Program {
        static void Main(string[] args) {

            while (true) {

                int[] ar = NextInts();
                if (ar[0] == 0 && ar[1] == 0) return;
                int start = 1, end = ar[0];
                int sum = ar[1];
                int ans = 0;

                for (int i = start; i <= end - 2; i++) {
                    for (int j = i + 1; j <= end - 1; j++) {
                        for (int k = j + 1; k <= end; k++) {
                            if (i + j + k == sum) ans++;
                        }
                    }
                }

                Println(ans);

            }

        }

        public static void Print (Object o) {
            Console.Write(o);
        }

        public static void Println (Object o) {
            Console.WriteLine(o);
        }

        public static string NextString() {
            return Console.ReadLine();
        }

        public static string[] NextStrings () {
            return Console.ReadLine().Split();
        }

        public static int NextInt () {
            return int.Parse(Console.ReadLine());
        }

        public static int[] NextInts () {
            string[] a = Console.ReadLine().Split();
            int[] b = new int[a.Length];
            for (int i = 0; i < a.Length; i++) {
                b[i] = int.Parse(a[i]);
            }
            return b;
        }

        public static double NextDouble () {
            return double.Parse(Console.ReadLine());
        }

    }
}