#include <set>
#include <string>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
int main() {
	cin.tie(0);
	ios_base::sync_with_stdio(false);
	int N;
	cin >> N;
	vector<string> A(N), B(N), seq;
	set<string> S;
	for (int i = 0; i < N; ++i) {
		cin >> A[i] >> B[i];
		if (S.find(B[i]) == S.end()) {
			S.insert(B[i]);
			seq.push_back(B[i]);
		}
	}
	sort(A.begin(), A.end());
	for (string s : seq) {
		if (!binary_search(A.begin(), A.end(), s)) {
			cout << s << '\n';
		}
	}
	return 0;
}