#include <cstdio>
#include <iostream>
#include <string>
#include <sstream>
#include <stack>
#include <algorithm>
#include <cmath>
#include <queue>
#include <map>
#include <set>
#include <cstdlib>
#include <bitset>
#include <tuple>
#include <assert.h>
#include <deque>
#include <bitset>
#include <iomanip>
#include <limits>
#include <chrono>
#include <random>
#include <array>
#include <unordered_map>
#include <functional>
#include <complex>

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

const long long MAX = 5100000;
const long long INF = 1LL << 60;
const long long mod = 1000000007LL;
//const long long mod = 998244353LL;

using namespace std;
typedef unsigned long long ull;
typedef long long ll;


int main()
{
	/*
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	*/

	vector<vector<int>> g(26);
	ll N; cin >> N;
	vector<int> v;
	for (ll i = 0; i < N; i++) {
		string s; cin >> s;
		for (ll j = 0; j < s.size(); j++) {
			v.push_back(s[j] - 'A');
			if (j < (ll)s.size() - 1) {
				g[s[j] - 'A'].push_back(s[j + 1] - 'A');
			}
		}
	}
	ll M; cin >> M;
	for (ll i = 0; i < M; i++) {
		string s; cin >> s;
		for (ll j = 0; j < s.size(); j++) {
			v.push_back(s[j] - 'A');
			if (j < (ll)s.size() - 1) {
				g[s[j] - 'A'].push_back(s[j + 1] - 'A');
			}
		}
	}

	for (ll i = 0; i < 26; i++) {
		sort(g[i].begin(), g[i].end());
		g[i].erase(unique(g[i].begin(), g[i].end()), g[i].end());
		if (g[i].size() > 1) {
			puts("-1");
			return 0;
		}
	}
	sort(v.begin(), v.end());
	v.erase(unique(v.begin(), v.end()), v.end());
	vector<ll> deg(26);
	for (auto p : v) {
		//cout << p << endl;
		if (g[p].size() == 0) continue;
		deg[g[p][0]]++;
		//cout << p << " " << g[p][0] <<  endl;
		if (deg[g[p][0]] > 1) {
			puts("-1");
			return 0;
		}
	}
	ll start = -1;
	for (auto p : v) {
		if (deg[p] == 0) {
			if(start == -1) start = p;
			else {
				puts("-1");
				return 0;
			}
		}
	}
	cout << (char)(start + 'A');
	while (g[start].size() != 0) {
		start = g[start][0];
		cout << (char)(start + 'A');
	}
	cout << endl;
	return 0;
}