#include<bits/stdc++.h>
using namespace std;
#define int64_t long long
#define mp make_pair
#define pb push_back
#define all(x) (x).begin(), (x).end()
void Solve(void) {
int N; cin >> N;
multiset<string> names;
for (int i = 1; i <= N; i ++) {
string s; cin >> s;
names.insert(s);
}
for (int i = 1; i < N; i ++) {
string s; cin >> s;
names.erase(names.find(s));
}
cout << (*names.begin());
}
signed main() {
ios_base::sync_with_stdio(false); cin.tie(0);
int Tests = 1; // cin >> Tests;
while (Tests --) {
Solve();
}
}
