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

while(1) {
    fscanf(STDIN, "%d %d", $n, $x);
    if ($n === 0 && $x === 0) {
        return;
    }

    $count = 0;
    for ($i = 1; $i <= $n -2; ++$i) {
        for ($j = $i + 1; $j <= $n - 1; ++$j) {
            for ($k = $j + 1; $k <= $n; ++$k) {
                if ($i + $j + $k === $x) {
                    ++$count;
                }
            }
        }
    }
    echo $count, PHP_EOL;
}