#include <bits/stdc++.h>
#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
#include<string>
using ll = long long;
using namespace std;

int main()
{
    ll n;
    cin >> n;
    vector<string> a(n), b(n-1);
    for (int i = 0; i < n; i++) cin >> a[i];
    for (int i = 0; i < n-1; i++) cin >> b[i];
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    for (int i = 0; i < n-1; i++) {
        if (a[i] != b[i]){
            cout << a[i] << endl;
            return 0;
        }
    }
    cout << a[n-1] << endl;
}