/*
ID: 5ak0
PROG:
LANG: C++11
*/
#include <bits/stdc++.h>
#define fr first
#define sc second
#define pb push_back
#define mpr make_pair
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int INF = 1e9 + 7;
int n;
string s, x;
map <string, int> mp;
int main(){
#ifndef SAKO
//freopen(".in", "r", stdin);
//freopen(".out", "w", stdout);
#endif // SAKO
ios_base::sync_with_stdio(0);
cin >> n;
for (int i = 1; i <= n; ++i){
cin >> s;
++mp[s];
}
for (int i = 1; i < n; ++i){
cin >> x;
--mp[x];
}
for (auto to : mp)
if (mp[to.first])
cout << to.first;
return 0;
}
