///////////////////////////////////////////////////////////////////////////////////////////////
#include <bits/stdc++.h>
using namespace std;
// #define int long long
#define FAST_IO ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define FILE_IO(x) freopen((string(x) + ".in").c_str(), "r", stdin); freopen((string(x) + ".out").c_str(), "w", stdout)
#define f first
#define s second
#define x1 x1qwer
#define y1 y1qwer
#define right right123
#define left left123
#define foreach(it, v) for (auto it : v)
#define rep(it, n) for (int it = 0; it < n; ++it)
#define forin(it, l, r) for (int it = l; it < r; ++it)
#define all(x) x.begin(), x.end()
typedef long long ll;
typedef unsigned long long ull;
typedef double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
const double DINF = numeric_limits<double>::infinity();
const ll MOD = 1e9 + 7;
const double EPS = 1e-7;
ll gcd(ll a, ll b) { return b ? gcd(b, a % b) : a; }
mt19937 mmtw_(MOD);
uniform_int_distribution<ll> rd_;
ll randomll() { return rd_(mmtw_);}
ll rnd(ll x, ll y) { return rd_(mmtw_) % (y - x + 1) + x; }
template <class T> T fact(T n) { if (n == 1) return 1; return n * fact(n - 1); }
////////////////////////////////////////////////////////////////////////////////////////////////
int n;
unordered_multiset<string> s;
int main() {
FAST_IO;
cin >> n;
rep(i, n) {
string a;
cin >> a;
s.insert(a);
}
rep(i, n - 1) {
string a;
cin >> a;
s.erase(s.find(a));
}
cout << (*s.begin()) << endl;
}
