import java.io.*;
import java.util.*;
import java.util.function.*;
import java.util.stream.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner();
        int n = sc.nextInt();
        Map<String, Integer> counts = new HashMap<>();
        for (int i = 0; i < n; i++) {
            String name = sc.next();
            counts.put(name, counts.getOrDefault(name, 0) + 1);
        }
        while (n-- > 1) {
            String name = sc.next();
            counts.put(name, counts.get(name) - 1);
        }
        System.out.println(counts.keySet().stream().filter(x -> counts.get(x) == 1).findFirst().orElse(""));
    }
}
class Scanner {
    BufferedReader br;
    StringTokenizer st = new StringTokenizer("");
    StringBuilder sb = new StringBuilder();
    
    public Scanner() {
        try {
            br = new BufferedReader(new InputStreamReader(System.in));
        } catch (Exception e) {
            
        }
    }
    
    public int nextInt() {
        return Integer.parseInt(next());
    }
    
    public long nextLong() {
        return Long.parseLong(next());
    }
    
    public double nextDouble() {
        return Double.parseDouble(next());
    }
    
    public String next() {
        try {
            while (!st.hasMoreTokens()) {
                st = new StringTokenizer(br.readLine());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            return st.nextToken();
        }
    }
    
}