#include<iostream>
#include<vector>
#include<algorithm>
#include<cmath>
#include<string>
#include<iomanip>
#include<numeric>
#include<queue>
#include<deque>
#include<stack>
#include<set>
#include<map>
#include<random>
using namespace std;
typedef long long ll;
const int mod=998244353;
int main(){
	int n;
	string a,b;
	cin>>n;
	multiset<string>ms;
	for(int i=0;i<n;i++){
		cin>>a;
		ms.insert(a);
	}
	while(cin>>b)
		ms.erase(ms.find(b));
	cout<<*ms.begin()<<endl;
}