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: Accepted)

readlines.each do |line|
  n, x = line.split.map(&:to_i)
  break if n == 0 && x == 0

  solves = []
  # i + j + j == x
  (1..n - 2).each do |i|
    # j + k == x - i
    (i + 1..n - 1).each do |j|
      # k == x - i - j
      k = x - i - j
      solves << [i, j, k] if j < k && k <= n
    end
  end
  puts solves.count
end