def array_integer(a)
	0.upto(a.count) {|x|
		a[x] = a[x].to_i
	}
	return a
end

eof = false

until eof do
	n,x = array_integer(STDIN.gets.split(" "))
	
	if n == 0 && x == 0 then
		eof = true
		break
	end

	if x < 6 then
		print "0\n"
		next
	end

	answer_num = 0
	
	
	1.upto(n-2) {|i|
		if ((i * 3) + 2) > x then
			break
		end
		(i+1).upto(n-1) {|j|
			if (i + (j * 2) + 1) > x then
				break
			end
			(j+1).upto(n) {|k|
				if i + j + k > x then
					break
				elsif i + j + k == x then
					answer_num += 1
				end
			}
		}
	}
	print answer_num, "\n"
end

