import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc= new Scanner(System.in);
		int n, x;
		while (sc.hasNext()) {
			int count = 0;
			n = Integer.parseInt(sc.next());
			x = Integer.parseInt(sc.next());
			if (n == 0 && x == 0) break;
			for (int i=1; i < n+1; i++) {
				for (int j=i+1; j < n+1; j++) {
					for (int k=j+1; k < n+1; k++) {
						if (i + j + k == x) count++;
					}
				}
			}
			System.out.println(count);
		}
		sc.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