import java.util.Scanner;

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