import java.util.*;

public class Main {
	public static void main(String[] args) {
		@SuppressWarnings("resource")
		Scanner sc = new Scanner(System.in);
		while (true) {
			int n = sc.nextInt();
			int x = sc.nextInt();
			if (n == 0 && x == 0)
				break;
			int count = 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)
							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