import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner scan=new Scanner(System.in);
		int n,x,ans;
		while(true){
			n=scan.nextInt();
			x=scan.nextInt();
			ans=0;
			if(n==0&&x==0) break;
			for(int i=1;i<=n;i++){
				for(int j=i+1;j<=n;j++){
					for(int k=j+1;k<=n;k++){
						if(i+j+k==x){
							ans++;
							break;
						}
						if(x<i+j+k){
							break;
						}
					}
					if(x<=i+j){
						break;
					}
				}
				if(x<=i){
					break;
				}
			}
			System.out.println(ans);
		}
		scan.close();
	}
}
/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