import java.util.Scanner;

/**
 *
 * @author k16075kk
 */
public class Main {

    /**
     * @param args the command line arguments
     */
    static char[] xx = new char[]{'S', 'H', 'C', 'D'};

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        while (true) {
            int n = sc.nextInt();
            int x = sc.nextInt();
            if (n == 0 && x == 0) {
                break;
            }
            int count = 0;
            for (int i = 1; i <= n; i++) {
                for (int j = i + 1; j <= n; 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