class Program
    {
       static void Main(string[] args)
        {
           string template = "mongodb://{0}:{1}@{2}/?replicaSet=rs0&readpreference={3}";
           string username = "root";
           string password = "rootroot";
           string clusterEndpoint = "sample-cluster.cluster-cqjaxx9hbhi0.us-west-2.docdb.amazonaws.com:27017";
           string readPreference = "secondaryPreferred";

           string connectionString = String.Format(template, username, password, clusterEndpoint, readPreference);
           var settings = MongoClientSettings.FromUrl(new MongoUrl(connectionString));
           var client = new MongoClient(settings);

           var database = client.GetDatabase("library");
           var collection = database.GetCollection<BsonDocument>("Books");

           var docToInsert = new BsonDocument { { "title", "Harry Potter" } };
           collection.InsertOne(docToInsert);
        }
    }