#include <bits/stdc++.h>
#define endl '\n'
#define space ' '
#define st first
#define nd second
#define pb push_back
#define mp make_pair
#define ii pair <int,int>
#define iii pair < int,pair <int,int> >
#define vi vector <int>
#define vii vector < pair<int,int> >
#define forr(i,A,B) for(int i=A;i<B;++i)
#define input(file) freopen(file,"r",stdin)
#define output(file) freopen(file,"w",stdout)
using namespace std;
int n;
map<string,int> h;
int main(){
cin>>n;
forr(i,0,n){
string s;
cin>>s;
h[s]++;
}
forr(i,0,n-1){
string s;
cin>>s;
h[s]--;
}
for(auto it=h.begin();it!=h.end();it++){
if((it->nd)>0){
cout<<(it->st)<<endl;
break;
}
}
return 0;
}
