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)

cnt = 0
loop do
    input = gets.split(" ").map do |i| i.to_i end
    if input[0] == 0 && input[1] == 0
        break
    else
        (1..input[0]).each do |n1|
            (n1+1..input[0]).each do |n2|
                (n2+1..input[0]).each do |n3|
                    if n1 + n2 + n3 == input[1]
                        cnt += 1
                    end
                end
            end
        end
    end
    puts cnt
    cnt = 0
end