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)

class Counter
  @@max_size = 3
  def initialize(max, cond)
    @max = max
    @cond = cond
    @queue = []
    @count = 0
  end
  def run
    @queue << [1, @max, []]
    while @queue.size > 0 do
      task = @queue.shift
      from, to, nums = task
      (from..to).each do |i|
        new_nums = nums + [i]
        if new_nums.size >= @@max_size
          if new_nums.reduce{|sum, n| sum + n} == @cond
            @count += 1
          end
        else
          if i + 1 < @max
            @queue << [i + 1, @max, new_nums]
          end
        end
      end
    end
    return @count
  end
end

lines = STDIN.read.split("\n")
lines.each do |line|
  n, x = line.split(' ').map(&:to_i)
  break if n == 0 && x == 0
  puts Counter.new(n, x).run()
end