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 Ruby (judge verdict: Wrong Answer)

n, x = gets.split.map(&:to_i)
cnt = 0
(1..n-2).each do | i |
  (i+1..n-1).each do | j |
    (j+1..n).each do | k |
      cnt += 1 if i + j + k == x
    end
  end
end
puts cnt