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)

def read_inputs
  inputs = []
  loop do
    input = gets.split(" ").map(&:to_i)
    case input
      when [0, 0] then break
      else inputs << input
    end
  end
  inputs
end

def countWays(n, x)
  (1..n).map {|a|
    sb = a + 1
    next 0 if sb > n
    [*sb..n].map {|b|
      sc = b + 1
      next 0 if sc > n
      [*sc..n].map {|c|
        next 0 if a == b || b == c || a == c
        next 1 if a + b + c == x
        0
      }.inject(:+)
    }.inject(:+)
  }.inject(:+)
end

inputs = read_inputs
puts inputs.map {|i| countWays(*i)}.join("\n")