#include <iostream>
#include <cassert>
#include <set>
#include <vector>

using namespace std;

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);

  int N; cin >> N;
  vector<string> memo(N);
  multiset<string> A, B;
  for (int i = 0; i < N; i++) {
    string a; cin >> a;
    A.insert(a);
    memo[i] = a;
  }
  for (int i = 0; i < N - 1; i++) {
    string b; cin >> b;
    B.insert(b);
  }

  for (string &a: memo) {
    if (A.count(a) != B.count(a)) {
      cout << a << endl;
      break;
    }
  }
  return 0;
}