import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int jouken = 0;

        while (jouken == 0) {
            int n = scanner.nextInt();
            int x = scanner.nextInt();
            int kazu = 0;
            if (n == 0 && x == 0) {
                break;
            }
            for (int i = 1; n >= i; i++) {
                for (int j = 1; n >= j; j++) {
                    for (int k = 1; n >= k; k++) {
                        int goukei = i + j + k;
                        if (i != k && k != j && j != i && goukei == x&&i>j&&j>k) {
                            kazu++;
                        }
                    }
                }
            }
            System.out.println(kazu);
        }
    }
}
/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