#include <bits/stdc++.h>
using namespace std;
#define rep(i,a,b) for(LL i = a;i<b; i++)
#define rrep(i,a,b) for(LL i = a;i>b; i--)
#define tobirep(i,a,b,c) for(LL i = a;i<b; i+=c)
#define tobirrep(i,a,b,c) for(LL i = a;i>b; i-=c)
#define INF ((1LL<<62)-(1LL<<31))
#define ooki 9223372036854775807
#define tii -9223372036854775808
typedef long long LL;
int main(){
   LL n;
  cin >> n;
  vector<string> a(n);
  vector<string> b(n-1);
  rep(i,0,n){cin >> a[i];}
  rep(i,0,n-1){cin >> b[i];}
  sort(a.begin(),a.end());
  sort(b.begin(),b.end());
  rep(i,0,n-1){
    if(a[i]!=b[i]){cout << a[i] << '\n';return 0;}
  }
  cout << a[n-1] << '\n';
}