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)

while (ln = gets.chomp) != '0 0' do
  n, x = ln.split.map(&:to_i)
  a1 = 1
  a2 = 2
  a3 = 3
  cnt = 0
  while true do
    cnt += 1 if a1 + a2 + a3 == x
    puts "#{a1} + #{a2} + #{a3} = " + (a1+a2+a3).to_s
    if a3 >= n || a1 + a2 + a3 >= x
      if a2 + 1 == a3 || a1 + a2 + a3 >= x
        if a1 + 1 == a2
          break
        else
          a1 += 1
          a2 = a1 + 1
          a3 = a1 + 2
        end
      else
        a2 += 1
        a3 = a2 + 1
      end
    else
      a3 += 1
    end
  end
  puts cnt
end