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)

loop do
  ans = 0
  a, b, c = [1, 2, 3]
  n, x = gets.split.map(&:to_i)
  break if n == 0 && x == 0
  loop do
    ans += 1 if a + b + c == x
    puts "a: #{a}, b: #{b}, c: #{c} = #{a+b+c}"
    if c < n && a + b + c < x
      c += 1
    else
      if b+1 == c
        if a+1 == b
          break
        else
          a += 1
          b = a+1
          c = b+1
        end
      else
        b += 1
        c = b+1
      end
    end
  end
  puts ans
end