#include <bits/stdc++.h>
#define NIL (-1)
#define ll long long
using namespace std;
const int64_t MOD = 1e9 + 7;
const int INF = INT_MAX;
const double PI = acos(-1.0);

int main() {
	int N;
	cin >> N;

	vector<string> A(N), B(N - 1);
	map<string, int> mp1,mp2;
	for (int i = 0; i < N; i++) {
		cin >> A[i];
		mp1[A[i]]++;
	}
	for (int i = 0; i < N-1; i++) {
		cin >> B[i];
		mp2[B[i]]++;
	}

	for (int i = 0; i < N; i++) {
		string s = A[i];
		if (mp1[s] != mp2[s]) {
			cout << s << endl;
			break;
		}
	}

	return 0;
}