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 conb{
    public static void Main(){
        String temp = Console.ReadLine();
        while(!temp.Equals("0 0")){
            String[] str = temp.Split(' ');
            int n = int.Parse(str[0]);
            int x = int.Parse(str[1]);
            int count = 0;
            int i,j,k;
            for(i=1; i<=n; i++){
                j=i+1;
                for(j=i+1; j<=n; j++){
                    k=j+1;
                    for(k=j+1; k<=n; k++){
                        if(i!=j || j!=k|| i!=k){
                            if(i+j+k == x){
                                count++;
                            }
                        }
                    }
                }
            }
            Console.WriteLine("{0}",count);
            temp = Console.ReadLine();
        }
    }
}