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: Time Limit Exceeded)

<?php
while(1){
  list($n,$x)=explode(' ',trim(fgets(STDIN)));

  if(!$n||!$x) break;

  $ok=0;
  for($i=1;$i<=$n;$i++) if(solve(0,$i)) ++$ok;

  echo $ok,PHP_EOL;
}

function solve($sum,$num){
  global $n,$x;
  if($num>$n){return false;}

  if($sum==$x){return true;}

  if(solve($sum+$num,$num+1)){return true;}#use $num
  return solve($sum,$num+1);#not use $num
}