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( 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;
            }

            int count = 0;
            int m = x / 3;

            for ( int a = 1; a < m; ++a ) {
                for ( int b = a + 1; b < n; ++b ) {
                    if ( x < a + b * 2 + 1 ) {
                        continue;

                    } else if ( x > a + b + n ) {
                        continue;
                    }

                    count += 1;
                }
            }

            Console.WriteLine( count );
        }
    }
}