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 line = gets
	n, x = line.split( " " ).map { | val | val.to_i }
	break if 0 == n && 0 == x

	cnt = 0
	goto = false
	for i in ( 1 .. n-2 )
		break if x < 3*(i+1)
		for j in ( i+1 .. n-1 )
			break if x < i+j
			for k in ( j+1 .. n )
				s = ( i + j + k )
				if x < s
					goto = true
					break
				elsif x == s
					cnt += 1
					break
				end
			end
			break if goto
		end
		goto = false
	end
	
	puts( cnt )
end