#include <stdio.h>
#include <iostream>
#include <queue>
#include <string>

using namespace std;

int main() {
  int N; cin >> N;
  queue<string> Q;

  for (int i = 0; i < N; i++) {
    string S; cin >> S;

    Q.push(S);
  }

  for (int i = 0; i < N - 1; i++) {
    string S; cin >> S;
    
    if (Q.front() != S) {
      break;
    }

    Q.pop();
  }

  cout << Q.front() << endl;
  
  return 0;
}