#include <bits/stdc++.h>
#define add emplace_back
#define fi first
#define se second
using namespace std;
using ll = long long;
using pll = pair<ll,ll>;
using pii = pair<int,int>;
const int maxn = 105;
int n;
unordered_map<string,int> mp;
int main () {
ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
cin >> n;
for (int i = 0;i < n; i++) {
string s; cin >> s;
mp[s]++;
}
for (int i = 1;i < n; i++) {
string s; cin >> s;
mp[s]--;
}
for (pair<string,int> c : mp) {
if (c.se > 0) {
cout << c.fi << "\n";
return 0;
}
}
return 0;
}
