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)

def how_many_ways(n, x)
  ary = [*1..n].combination(3).to_a
  cnt = 0
  ary.each do |i|
    cnt += 1 if i.inject(&:+) == x
  end
  return cnt
end

loop do
  n, x = gets.chomp.split(" ").map(&:to_i)
  break if [n, x] == [0, 0]
  puts how_many_ways(n, x)
end