#include<bits/stdc++.h>
using namespace std;
//#define int long long
#define REP(i,m,n) for(int i=(m);i<(n);i++)
#define rep(i,n) REP(i,0,n)
#define pb push_back
#define all(a) a.begin(),a.end()
#define rall(c) (c).rbegin(),(c).rend()
#define mp make_pair
#define endl '\n'
#define vec vector<ll>
#define mat vector<vector<ll> >
#define fi first
#define se second
#define double long double
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
//typedef long double ld;
typedef complex<double> Complex;
const ll INF=1e9+7;
const ll MOD=998244353;
const ll inf=INF*INF;
const ll mod=MOD;
const ll MAX=2000010;



signed main(){
    ll n;cin>>n;
    map<string,ll>a,b;
    rep(i,n){
        string s;cin>>s;
        a[s]++;
    }
    rep(i,n-1){
        string t;cin>>t;
        b[t]++;
    }
    for(auto e:b){
        if(e.se!=a[e.fi]){
            cout<<e.fi<<endl;
            return 0;
        }
    }
}