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 C (judge verdict: Time Limit Exceeded)

#include<stdio.h>
int main(void){
   int n, k, key = 1, a, b, c, count;
   scanf("%d %d", &n, &k);
   while ( key ) {
      count = 0;
      a = 1;
      while ( a <= n ) {
         b = a + 1;
         while ( b <= n ) {
            c = b + 1;
            while ( c <= n ) {
               if ( k == a + b + c ) /*{ printf("%d %d %d\n", a, b, c); count++;}*/
            c++;
            }
         b++;
         }
      a++;
      }
      printf("%d\n", count);
      scanf("%d %d", &n, &k);
      if ( n == 0 && k == 0 ) key = 0;
   }
   return 0;
}