import java.io.IOException;
import java.util.Scanner;
 
public class Main {
 
    public static void main(String[] args) throws IOException {
        Scanner sc = new Scanner(System.in);
       
        while (true) {
            String[] data = sc.nextLine().split(" ");
            int n = Integer.parseInt(data[0]);
            int x = Integer.parseInt(data[1]);
            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