import java.util.Scanner;

public class Main {
	public static void main(String[] args)
	{
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		int x = scan.nextInt();
		int count = 0;
		while(n != 0 || x != 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){count++;}
					}
				}
			}
			System.out.println(count);
			n = scan.nextInt();
			x = scan.nextInt();
			count = 0;
		}
	}
}
/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