import java.util.Scanner;

// (1) ????????????????????????
	// (1.1) n???????????????
	// (1.2) x???????????????
	// (1.3) n??¨x???0?????????????????????????????????????????????
	// (1.4) ?????????????????????????????\???????????°sum????????????0??§????????????
	// (1.5) i???1??????(n - 2)????????\?????????????????????
		// (1.5.1) j???i + 1??????(n - 1)????????\?????????????????????
			// (1.5.1.1) k???j + 1??????n????????\?????????????????????
				// (1.5.1.1.1) ?????????(i + j + k)???x????????°?????\?????????????????????
					// (1.5.1.1.1.1) sum?????°???1?¢???????
	// (1.6) ????????????????????°?????¨?????????
// (2) scan?????????????????????
public class Main {

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

			int n = scan.nextInt();
			int x = scan.nextInt();

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

			int sum = 0;

		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) {
						sum++;
					}
				}
			}
		}
		System.out.println(sum);
		}
		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