std::vector<word> words;

void routine_A() {
    lock = lockUnique(mtx);
    while (!words.empty) {
        cout << words[0];
        words.pop();
        cv.notify_one();
        cv.wait(lock);
    }
}

void routine_B() {
    lock = lockUnqiue(mtx);
    while (!words.empty) {
        cout << words[0];
        words.pop();
        cv.notify_one();
        cv.wait(lock);
    }
}