/**
 *   @FileName	a.cpp
 *   @Author	kanpurin
 *   @Created	2021.04.04 19:18:41
**/

#include "bits/stdc++.h" 
using namespace std; 
typedef long long ll;

int main() {
    int n;cin >> n;
    unordered_map<string,int> mp;
    for (int i = 0; i < n; i++) {
        string s;cin >> s;
        mp[s]++;
    }
    for (int i = 0; i < n-1; i++) {
        string s;cin >> s;
        mp[s]--;
    }
    for(auto [key,val] : mp) {
        if (val != 0) {
            cout << key << endl;
            return 0;
        }
    }
    assert(true);
    return 0;
}