#include <iostream>
#include <queue>
#include <string>
#include <cctype>
using namespace std;

class ClinicQueueManager {
private:
    queue<string> q;
public:
    void addVisitor(const string &name) {
        q.push(name);
    }

    void nextVisitor() {
        if (q.empty()) {
            cout << "the line was empty" << endl;
        } else {
            cout << q.front() << endl;
            q.pop();
        }
    }

    static bool isValidName(const string &name) {
        if (name.empty()) return false;
        for (char c : name) {
            if (!isalpha(static_cast<unsigned char>(c))) return false;
        }
        return true;
    }
};

int main() {
    int n;
    if (!(cin >> n) || n < 1 || n > 100) {
        cout << "Invalid input" << endl;
        return 0;
    }

    ClinicQueueManager manager;
    for (int i = 0; i < n; i++) {
        string input;
        if (!(cin >> input)) {
            cout << "Invalid input" << endl;
            return 0;
        }

        if (input == "-") {
            manager.nextVisitor();
        } else {
            if (!ClinicQueueManager::isValidName(input)) {
                cout << "Invalid input" << endl;
                return 0;
            }
            manager.addVisitor(input);
        }
    }

    return 0;
}