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 PHP (judge verdict: Accepted)

<?php
$input = STDIN;

while (true) {
    list($n, $x) = explode(' ', trim(fgets($input)));

    if ($n == 0 && $x == 0) break;

    $min_a = max(intval($x / 3) + 1, 3);
    $max_a = min($n, $x - 3);
    $cnt = 0;

    for ($a = $min_a; $a <= $max_a; $a++) {
        $rest = $x - $a;
        $min_b = max(intval($rest / 2) + 1, 2);
        $max_b = min($rest - 1, $a - 1);

        $cnt += ($max_b - $min_b + 1);
    }

    print "{$cnt}\n";
}