set<int> getSetFromFile(string path) {
    bool isCorrect;
    string temp;
    set<int> arr[3];
    int num, size;
    //int size = getSizeForSetFromFile(path);
    ifstream fin;
    isCorrect = true;
    fin.open(path);

    for (int i = 0; i < 3; i++) {
        do {
            isCorrect = true;
            fin >> size;
            if (fin.fail()) {
                isCorrect = false;
                fin.clear();
                cout << "Check the correctness of the entered data from the file.\n";
                path = getPath();
            }
            if (isCorrect && (size > 15 || size < 1)) {
                isCorrect = false;
                cout << "check the correctness of the entered data from the file.\n";
                path = getPath();
            }
        } while (!isCorrect);

        //fin >> temp;
        for (int j = 0; j < size; j++) {
            do {
                isCorrect = true;
                fin >> num;
                if (fin.fail()) {
                    isCorrect = false;
                    cout << "Invalid data in the file.\n";
                    path = getPath();
                }
            } while (!isCorrect);
            arr[i].insert(num);
        }
    }
    fin.close();
    return arr;
}