#include <bits/stdc++.h>
#include <iostream>
#include <stack>
#include <vector>
#include <set>
#include <queue>
#include <string>
#include <algorithm>
#include <unordered_map>
#include <unordered_set>
#include <map>
using namespace std;
typedef long double ld;
mt19937_64 rnd(chrono::steady_clock::now().time_since_epoch().count());
//#define int long long
#define double long double
#define all(x) (x).begin(), (x).end()
#define pii pair<int, int>
#define lowbit(x) x & (-x);
#define inf 1e18
#define _inf -1e18
#define pyes cout << "YES" << endl
#define pno cout << "NO" << endl
#define inv(a) for (int& x: a) cin >> x;
#define llv(a) for (ll& x: a) cin >> x;
#define pri(a) for (int& x: a) cout << x << '\n'
int const MOD = 998244353;
int const lg = 20;
int const block = 500;
// int block;
int const MAX = 3e5 + 1, N = 4000;
int n, m, q, k;
void bexuyen67() {
cin >> n;
vector<string> s(n);
map<string, int> mp;
for (string& x: s){
cin >> x;
mp[x]++;
}
for (int i = 1; i < n; i++){
string x;
cin >> x;
mp[x]--;
}
for (auto [ss, cnt]: mp){
if (cnt){
cout << ss;
return;
}
}
}
signed main() {
#ifdef binhball
freopen("input.txt", "r", stdin);
freopen("output.txt", "w", stdout);
#endif
cin.tie(0)->sync_with_stdio(0);
cout << fixed << setprecision(15);
int t = 1;
// cin >> t;
while (t--)
bexuyen67();
}
