#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define vi vector<int>
#define vll vector<ll>
#define vii vector<pair<int,int>>
#define vlll vector<pair<ll,ll>>
#define all(x) x.begin(),x.end()
#define TESTCASES ll t;cin>>t;while(t--)
using namespace std;
int main()
{
ll n;cin>>n;set<string> start,end;
for(int i=1;i<=n;i++)
{
string s;cin>>s;
start.insert(s);
}
for(int i=1;i<n;i++)
{
string t;cin>>t;
end.insert(t);
}
for(string x:start)
{
if(end.count(x))
continue;
else{cout<<x;break;}
}
}
