import java.util.Scanner;
class Main{
    int n,x,y=0,z=0;
    boolean a;
    String b;
    public void solve(){
        Scanner sc = new Scanner(System.in);
        sc.useDelimiter("\\s");
        while(a == false){
            n = sc.nextInt();
            x = sc.nextInt();
            if(n == 0 && x == 0){
                a = true;
                break;
            }
            for(int s1 = 1;s1 <= n-2; s1++){
                for(int s2 = s1+1;s2 <= n-1; s2++){
                    for(int s3 = s2+1;s3 <= n; s3++){
                        if(s1 == s2 || s1 == s3 || s2 == s3){
                            break;
                        }else if(s1 + s2 + s3 == x){
                            z++;
                        }
                    }
                }
            }
            System.out.println(z);
            z = 0;
        }
    }
    public static void main(String[] args){
        new Main().solve();
    }
}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz