#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    int32_t n;
    cin >> n;
    unordered_map<string, int32_t> hist;
    for (auto i = 0; i < n; ++i) {
        string s;
        cin >> s;
        ++hist[s];
    }
    for (auto i = 0; i < n - 1; ++i) {
        string s;
        cin >> s;
        --hist[s];
    }
    for (auto &&[k, v] : hist) {
        if (v == 1) {
            cout << k << endl;
            return 0;
        }
    }
    return 0;
}