import java.util.Scanner;

public class Main {
	public static void main(String[] args)
	{
		Scanner stdIn = new Scanner(System.in);
		
		while(true)
		{
			int n = stdIn.nextInt();
			int x = stdIn.nextInt();
			
			if(n==0 && x==0)
			{
				break;
			}
			
			int count = 0;
			
			for(int i=n;i>=3;i--)
			{
				for(int j=i-1;j>=2;j--)
				{
					for(int k=j-1;k>=1;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