import java.util.*;

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+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 && i!=j && j!=k && k!=i)
							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