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;

namespace ITP_7_B{
    public class Program{
        public static void Main(string[] args){
            while(true){
                string[] data = Console.ReadLine().Split(' ');
                int n = int.Parse(data[0]);
                int x = int.Parse(data[1]);

                //???????????¶
                if(n==0 && x==0) break;

                //?¨??????¨??????
                Console.WriteLine(GetCount(n,x));
            }
        }
        
        private static int GetCount(int max, int target){
            int count = 0;

            for(int i=1; i<=max-2; i++){
                for(int k=i+1; k<=max-1; k++){
                    for(int m=k+1; m<=max; m++){
                        int sum = i + k + m;
                        if(sum==target) count++;
                    }
                }
            }
            return count;
        }
    }
}