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 true
  n,x = gets.chomp.split(" ").map &:to_i
  break if n == 0 and x == 0

  c = 0
  n.times { |i|
    if i+2 <= n-1
      s = i+2
      (s..n).each { |j|
         if 0 < x-(i+1+j) and x-(i+1+j) <= n
           if x-(i+1+j) != i+1 and x-(i+1+j) != j
             c += 1
           end
          end
      }
    end
  }
  puts c
end