#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#ifdef LOCAL
#include "algo/debug.h"
#else
#define debug(...) (void(0))
#endif
void run_case();
int main() {
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(nullptr);
	int T = 1;
	// cin >> T;
	while (T--) run_case();
	return 0;
}
void run_case() {
	int N;
	cin >> N;
	map<string, int> MA, MB;
	for(int i = 0; i < N; i++) {
		string a;
		cin >> a;
		MA[a]++;
	}
	for(int i = 0; i < N - 1; i++) {
		string b;
		cin >> b;
		MB[b]++;
	}
	for(const auto&[s,c]:MA) {
		if(MB[s] + 1 == c) {
			cout << s << "\n";
			return;
		}
	}
}