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 Python (judge verdict: Wrong Answer)

ans = 0
def do(nlist,x,c,index):
    global ans
    if x == 0:
        print "detect!"
        ans +=1
        return
    elif x < 0:
        return
    if c == 3:
        return
    if index < 0:
        return
    for i in reversed(xrange(0,index)):
        x -= nlist[i]
        print x
        do(nlist,x,c+1,index-1)
    return

while True:
    n,x = map(int,raw_input().split())
    if n==0 and x == 0:
        break
    nlist = [i for i in xrange(1,n+1)]
    print nlist
    do(nlist,x,0,len(nlist))
    print "ans : "+str(ans)
    # print ans
    ans = 0