#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    vector<string> names;
    set<string> cheat;
    for (int i = 0; i < N; i++) {
        string s, t;
        cin >> s >> t;
        cheat.insert(s);
        names.push_back(s);
        names.push_back(t);
    }
    for (auto &x : names) {
        if (!cheat.count(x)) {
            cout << x << endl;
            cheat.insert(x);
        }
    }
}