void sync_progress_file() {
    set<string> login_students_file;
    vector<string> users_in_progress_file;
    set<string> users_in_progress_file_set;

    ifstream students_file;
    students_file.open(MARK_BY_TOPIC_FILE);

    if (students_file.is_open()) {
        string line;
        int curr_index = 0;
        while (getline(students_file, line)) {
            if (curr_index % LOGIN_LINE_PERIOD_IN_STUDENTS_FILE == 0) {
                string subbed_login = line.substr(2, line.length());
                login_students_file.insert(subbed_login);
            }
            curr_index++;
        }
    }

    students_file.close();

    ifstream progress_file;
    progress_file.open(PROGRESS_FILE);

    if (progress_file.is_open()) {
        string line;
        int curr_index = 0;
        while (getline(progress_file, line)) {
            if (curr_index % LOGIN_LINE_PERIOD_IN_PROGRESSS_FILE == 0) {
                users_in_progress_file.push_back(line);
                users_in_progress_file_set.insert(line);
            }
            curr_index++;
        }
    }
    progress_file.close();

    if()

    for (string login : users_in_progress_file) {
        if (login_students_file.count(login) <= 0) {

        }
        else {
            cout << "Contains " << login << endl;
        }
    }

}