#include <bits/stdc++.h>
#define ff first
#define ss second
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;
void solve(){
int n;
cin >> n;
string s[n];
map<string,int> mp;
for(int i=0;i<n;i++){
cin >> s[i];
mp[s[i]]++;
}
for(int i=0;i<n-1;i++){
string c;
cin >> c;
mp[c]--;
}
for(int i=0;i<n;i++){
if(mp[s[i]]){
cout << s[i];
break;
}
}
}
int main(){
ios_base::sync_with_stdio(false);
cin.tie(nullptr);cout.tie(nullptr);
int t=1;
//cin>>t;
while(t--){
solve();
}
}
