import java.util.Scanner;

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

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

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

			int ans = 0;

			for (int a = 1; a <= n; a++)
			{
				for (int b = a + 1; b <= n; b++)
				{
					for (int c = b + 1; c <= n; c++)
					{
						if (a + b + c == x)
						{
							ans++;
						}
					}
				}
			}

			System.out.println(ans);
		}
	}
}


/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