#include <bits/stdc++.h>
using namespace std;
using ld = long double;
using ull = unsigned long long;
/*
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("-O3")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
*/
template <class T> inline T gcd(T a , T b) { return !a ? b : gcd(b % a , a); }
template <class T> inline T lcm(T a , T b) {return (a * b) / gcd(a , b) ; }
mt19937 rnd(time(0));
#define all(x) x.begin(), x.end()
#define debug(x) { cerr << #x << " = " << x << endl; }ы
void solve() {
int n;
cin >> n;
unordered_map<string, bool> cnt;
for (int i = 1; i <= n; i++) {
string name;
cin >> name;
cnt[name] ^= 1;
}
for (int i = 1; i < n; i++) {
string name;
cin >> name;
cnt[name] ^= 1;
}
for (auto it : cnt) {
if (it.second == 1) {
cout << it.first << '\n';
return;
}
}
return;
}
signed main() {
ios_base :: sync_with_stdio(0);
cin.tie(0) , cout.tie(0);
int t = 1;
while (t-- > 0) {
solve();
}
return 0;
}
