/*
Aliberk Sandıkçı
3 November 2021
Current Rank: Newbie
Current Grade: 10th in Izmir Science High School
*/
#include "bits/stdc++.h"
#define pb push_back
#define lwb lower_bound
#define upb upper_bound
#define fi first
#define se second
#define debu cout << "*debug*\n"
#define debug(x) cout << "debug " << x <<"\n"
#define int long long
constexpr int modn = 1e9+7; // 998244353
constexpr int maxn = 1e6+5;
constexpr int INF = 1e9+5;
using namespace std;
multiset<string> mts;
void solve(){
int n;
cin >> n;
string str;
for(int i=0;i<n;i++){
cin >> str;
mts.insert(str);
}
for(int i=0;i<n-1;i++){
cin >> str;
auto it = mts.find(str);
if(it!=mts.end()){
mts.erase(it);
}
}
cout << *(mts.begin());
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
//freopen("","r",stdin);
//freopen("","w",stdout);
int T=1;
//cin >> T;
while(T--){
solve();
}
return 0;
}
