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: Accepted)

#include<stdio.h>
int main(){
    int i,u,t,n,x,count,sum2 = 0,sum3 = 0;
    for(;;){
        scanf("%d %d",&n,&x);
        count = 0;
        if( n == 0 && x == 0){
            break;
        }
        for( i = 1 ; i <= n ; i += 1){
            for( u = 1 ; u <= n ; u += 1){
                sum2 = i + u;
                if( i == u ){
                    continue;
                }
                else{
                    for( t = 1 ; t <= n ; t += 1){
                        sum3 = sum2 + t;
                        if( i == t || u == t){
                            continue;
                        }
                        else if( sum3 == x){
                            count += 1;
                        }
                    }
                }
            }
        }
        printf("%d\n",count / 6);
    }
    return 0;
}