import java.util.Scanner;

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

		int way = 0;

		while(true) {
			int n = scan.nextInt();
			int x = scan.nextInt();

			if(n == 0 && x == 0) {
				break;
			}

			way = 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) {
							way++;
						}
					}
				}
			}
			System.out.println(way);
		}

		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