
import java.io.InputStreamReader;
import java.util.Scanner;

class Main {
	public static void main(String[] args) throws Exception {

		Scanner scanner = new Scanner(System.in);


		while (true) {
			int count = 0;
			int n = scanner.nextInt();
			int x = scanner.nextInt();
			if (n == 0 && x == 0) {
				break;
			} 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){
							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