class Message {
public: 
    Message() {}
    Message(string text, int id):msg_body(text), msg_id(id) {}
    const string& get_text() {
        return msg_body;
    }
    bool operator<(const Message& other) const {
        return this->msg_id < other.msg_id;
    }
    
private:
    string msg_body;
    int msg_id;
};

class MessageFactory {
public:
    MessageFactory() {}
    Message create_message(const string& text) {
        msg_counter += 1;
        return Message(text, msg_counter);
    }
private:
    int msg_counter = -1;
};