#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<climits>
#include<cmath>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<queue>
#include<numeric>
#include<functional>
#include<algorithm>
#include<bitset>
#include<tuple>
#include<unordered_set>
#include<unordered_map>
#include<random>
#include<array>
#include<cassert>
using namespace std;
#define INF (1<<29)
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define all(v) v.begin(),v.end()
#define uniq(v) v.erase(unique(all(v)),v.end())




int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);

	int n;
	unordered_set<string> c;
	vector<string> all;
	cin >> n;
	rep(i, n) {
		string a, b;
		cin >> a >> b;
		all.push_back(a);
		all.push_back(b);
		c.insert(a);
	}

	for (const string &s : all) {
		if (c.count(s) == 0) {
			cout << s << endl;
			c.insert(s);
		}
	}

	return 0;
}