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)

while ((n,x = gets.split(" ").map(&:to_i)).inject(:+) != 0) do
  max = 3*(n-1)
  if !((6..max).include?(x))
    puts 0
    next
  end
  count = 0
  catch(:stop) do
    n.downto(1) do |n1|
      (n1-1).downto(1) do |n2|
        n3 = x - n1 - n2
        count += 1 if (n3 < n2) && (n3 > 0)
        throw :stop if (n3 > n1)
        break if (n3 > n2)
      end
    end
  end
  puts count
end