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 x,n,i,j,k,z;
  z=0;
  
  while(1){
  scanf("%d %d",&x,&n);
  if(n==0 &&x==0){
     break;
    }    
    for(i=0;0<=i<=n-2;i++){
      for(j=i+1;j<=n-1;j++){
        for(k=j+1;k<=n;k++){
          if(i+j+k==x){
            ++z;
          }
        }
      }
    }
  printf("%d\n",z);
  }
  return 0;
}