#include <bits/stdc++.h>
#define ll long long
#define F first
#define S second
#define sz size()
using namespace std;
[[maybe_unused]]const int e6=1e6;
[[maybe_unused]]const int e7=1e7;
[[maybe_unused]]const int e8=1e8;
[[maybe_unused]]const int e9=1e9;
inline int rd(){
int num;cin>>num;
return num;
}
inline ll rdll(){
ll num;cin>>num;
return num;
}
[[maybe_unused]]const ll inf=1e18+7;
[[maybe_unused]]const ll MOD=1e9+7;
[[maybe_unused]]const int N=1e6+3;
void code(){
int n;cin>>n;
map<string,int>mp;
for(int i=1;i<=n;i++){
string s;cin>>s;
mp[s]++;
}
for(int i=1;i<=n-1;i++){
string s;cin>>s;
mp[s]--;
}
for(auto[to,cnt]:mp){
if(cnt!=0){
cout<<to;
break;
}
}
}
signed main(){
ios_base::sync_with_stdio(0);cin.tie(0);
int tt=1;
// cin>>tt;
while(tt--)code(),cout<<"\n";
}
