void lesson7() {
    map <string, string> dictionary;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        string key, value;
        cin >> key >> value;
        dictionary[key] = value;
    }
    string search_word;
    cin >> search_word;
    for (auto i : dictionary) {
        if (i.second == search_word) {
            cout << i.first;
        }
        if (i.first == search_word) {
            cout << i.second;
        }
    }
}

void lesson6() {
    set <int> numbers_one;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int value;
        cin >> value;
        numbers_one.insert(value);
    }
    set <int> numbers_two;
    int m;
    cin >> m;
    for (int i = 0; i < m; i++) {
        int value;
        cin >> value;
        numbers_two.insert(value);
    }
    vector <int> common_numbers;
    for (auto i = numbers_one.begin(); i != numbers_one.end(); i++) {
        if (numbers_two.find(*i) != numbers_two.end()) {
            common_numbers.push_back(*i);
        }
    }
    for (auto i : common_numbers) {
        cout << i << " ";
    }
}

void lesson5() {
    set <int> numbers_one;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int value;
        cin >> value;
        numbers_one.insert(value);
    }
    set <int> numbers_two;
    int m;
    cin >> m;
    for (int i = 0; i < m; i++) {
        int value;
        cin >> value;
        numbers_two.insert(value);
    }
    int count = 0;
    for (auto i : numbers_one) {
        if (numbers_two.find(i) != numbers_two.end()) {
            count++;
        }
    }
    cout << count;
}

void lesson4() {
    set <int> numbers;
    int n;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int value;
        cin >> value;
        if (numbers.find(value) == numbers.end()) {
            cout << "NO" << endl;
        }
        else {
            cout << "YES" << endl;
        }
        numbers.insert(value);
    }
}

void lesson3() {
    set <int> numbers;
    int n, count = 0;
    cin >> n;
    for (int i = 0; i < n; i++) {
        int value;
        cin >> value;
        if (numbers.find(value) == numbers.end()) {
            count++;
        }
        numbers.insert(value);
    }
    cout << count;
}