import java.util.Scanner;

class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		StringBuilder str = new StringBuilder();

		while (true) {
			int n = scan.nextInt();
			int x = scan.nextInt();
			int num = 0;
			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)
							num++;
					}
				}
			}
			if (n == 0 && x == 0)
				break;
			str.append(num + "\n");

		}
		System.out.print(str);

	}

}
/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