import java.util.*;
import java.io.*;
import java.math.*;
// import java.util.stream.Stream;

class Main{
    static BufferedReader buff = new BufferedReader(new InputStreamReader(System.in));
    static StringTokenizer st;
    static PrintWriter output = new PrintWriter(System.out);
    static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws IOException{
        int n = sc.nextInt();
        Map<String,Integer> A = new HashMap<>();
        Map<String,Integer> B = new HashMap<>();
        for(int i=0;i<n;i++) {
            String a = sc.next();
            if(!A.containsKey(a)) A.put(a,1);
            else A.put(a,A.get(a)+1);
        } 
        for(int i=0;i<n-1;i++) {
            String b = sc.next();
            if(!B.containsKey(b)) B.put(b,1);
            else B.put(b,B.get(b)+1);
        }
        String ans = "";
        for(String v : A.keySet()) {
            if(!B.containsKey(v)) {
                ans = v;
                break;
            }
            else if(A.get(v) > B.get(v)) {
                ans = v;
                break;
            }
        }
        output.print(ans);
        output.flush();
    }
}