import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            int n = scanner.nextInt();
            int x = scanner.nextInt();
            if (n == 0 && 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) 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