import java.util.*;

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();
			int cnt = 0;
			
			if (n==0 && x==0) {
				break;
			}
			
			for (int a=1 ; a<=n-2 ; a++) {
				for (int b=a+1 ; b<=n-1 ; b++) {
					for (int c=b+1 ; c<=n ; c++) {
						if(a+b+c == x) {
							cnt++;
						}
					}
				}
			}
			System.out.println(cnt+"");
		}
	}

}

/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