#include<bits/stdc++.h>
using namespace std;
#define int long long

signed main(){
	int n;
	cin >> n;
	vector<string> a(n);
	for(int i = 0; i < n; i++)cin >> a[i];

	int m;
	cin >> m;
	vector<string> b(m);
	for(int i = 0; i < m; i++)cin >> b[i];

	vector<string> str, str1;

	vector<int> tmp(n), tmp1(m);

	for(int i = 0; i < n; i++)tmp[i] = i;
	for(int i = 0; i < m; i++)tmp1[i] = i;
	string s;

	do{
		s = "";
		bool ok = false;
		for(int i = 0; i < n; i++)s += a[tmp[i]];
		for(int i = 0; i < str.size(); i++){
			if(str[i] == s)ok = true;
		}
		//cout << s << endl;
		if(!ok)str.push_back(s);

	}while(next_permutation(tmp.begin(), tmp.end()));

	do{
		s = "";
		bool ok = false;
		for(int i = 0; i < m; i++)s += b[tmp1[i]];
		for(int i = 0; i < str1.size(); i++){
			if(str1[i] == s)ok = true;
		}
		//cout << s << endl;
		if(!ok)str1.push_back(s);

	}while(next_permutation(tmp1.begin(), tmp1.end()));

	int count = 0;
	string ans;
	for(int i = 0; i < str.size(); i++){
		for(int j = 0; j < str1.size(); j++){
			if(str[i] == str1[j]){
				count++;
				ans = str[i];
			}
		}
	}
	
	if(count == 1)cout << ans << endl;
	else cout << -1 << endl;

}