import java.io.*;
import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        HashMap<String, Integer> counts = new HashMap<>();
        for (int i = 0; i < n; i++) {
            String name = sc.next();
            counts.put(name, counts.getOrDefault(name, 0) + 1);
        }
        for (int i = 0; i < n - 1; i++) {
            String name = sc.next();
            counts.put(name, counts.get(name) - 1);
        }
        for (String x : counts.keySet()) {
            if (counts.get(x) == 1) {
                System.out.println(x);
                return;
            }
        }
    }
}
class Scanner {
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    StringTokenizer st = new StringTokenizer("");
    
    public Scanner() throws Exception {
        
    }
    
    public int nextInt() throws Exception {
        return Integer.parseInt(next());
    }
    
    public long nextLong() throws Exception {
        return Long.parseLong(next());
    }
    
    public String next() throws Exception {
        if (!st.hasMoreTokens()) {
            st = new StringTokenizer(br.readLine());
        }
        return st.nextToken();
    }
}