#include <bits/stdc++.h>
#define ff first
#define ss second
#define endl '\n'
using namespace std;
const long long INF = (long long) 1e18;
const int mod = (int) 1e9+7;
const int MAXN = (int) 3e5+5;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
ll n;
vector<string> cont;
map<string, int> mp;
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
#ifdef Local
freopen("../IO/int.txt","r",stdin);
freopen("../IO/out.txt","w",stdout);
#endif
cin>>n;
for(int i = 0; i < n; i++){
string s;
cin>>s;
cont.push_back(s);
}
for(int i = 0; i < n - 1; i++){
string s;
cin>>s;
mp[s]++;
}
for(int i = 0; i < n; i++){
if(!mp[cont[i]]){
cout<<cont[i]<<endl;
break;
}
mp[cont[i]]--;
}
#ifdef Local
cout<<endl<<fixed<<setprecision(2)<<1000.0 * clock() / CLOCKS_PER_SEC<< " milliseconds ";
#endif
}
