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 ans (num, total, amax)
  if(total<=0)
    0
  elsif(num==1)
    if(total<=amax)
      1
    else
      0
    end
  else
    sum=0
    for i in 1..amax do
      sum+=ans(num-1,total-i,i-1)
    end
    sum
  end
end
      
  

while(true)
  a,b=gets.split(" ").map(&:to_i)
  if(a==0&&b==0) then
    break
  end
  d=ans(3,b,a)
  puts(d)
end