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 Python3 (judge verdict: Accepted)

import itertools

while True:
	n, x = map(int, input().split()) # n = 5, x = 9

	if (n == 0 and x == 0):
		break

	count = 0
	num_sequence = [i + 1 for i in range(n)] # [1, 2, 3, 4, 5]
	for guess in itertools.combinations(num_sequence, 3):
		sum = 0
		for i in guess:
			sum += i
		if (sum == x):
			# (1, 3, 5)
			# (2, 3, 4)
			count += 1

	print(count)