import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        while(sc.hasNext()){
            int n = sc.nextInt();
            int x = sc.nextInt();
            int count=0;

            if (n==0&&x==0)
                break;

            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