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)

while input = gets

    n, x = input.chomp.split(" ").map(&:to_i)
    
    if n == 0 && x == 0
        exit
    end
    
    ways = 0
    
    for i in 1..n - 2
    
        if i * 3 + 3 > x
            break
        end
    
        for j in i + 1..n - 1
        
            if i + j * 2 + 1 > x
                break
            end
        
            for k in j + 1..n
            
                if i + j + k > x
                    break
                elsif i + j + k == x
                    ways += 1
                end
            end
        end
    end
    
    puts ways
end