import java.util.Scanner;

public class Main {

	private static Scanner sc;

	public static void main(String[] args){
		sc = new Scanner(System.in);
		while(true){
			int n=sc.nextInt();
			int x=sc.nextInt();
			int a=0;
			if(n==0&&x==0)break;
			for(int i=1;i<=n-2;i++){
				for(int j=i+1;j<=n-1;j++){
					for(int k=j+1;k<=n;k++){
						if(i+j+k==x){
							a=a+1;
							break;
						}
					}
				}
			}
			System.out.println(a);
		}
	}
}
/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