import java.util.Scanner;

public class Main {
    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;

            int n1 = 1, n2 = 2, n3 = 3;

            for (n1 = 1; n1<= n - 2; n1++) {
                for (n2 = n1 + 1; n2<= n - 1; n2++) {
                    for(n3 = n2 + 1; n3 <= n; n3++){
                        if(n1 + n2 + n3 == 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