#include <bits/stdc++.h>
using namespace std;
int N, M, e, sum, deg[26]; bool ap[26], g[26][26]; string s, ret;
void dfs(int pos) {
	ret += pos + 65;
	for(int i = 0; i < 26; i++) {
		if(g[pos][i]) dfs(i);
	}
}
int main() {
	cin >> N;
	for(int i = 0; i < N; i++) {
		cin >> s; sum += s.size();
		for(int j = 0; j < s.size(); j++) ap[s[j] - 65] = true;
		for(int j = 1; j < s.size(); j++) {
			int a = s[j - 1] - 65, b = s[j] - 65;
			if(!g[a][b]) g[a][b] = true, deg[b]++, e++;
		}
	}
	cin >> M;
	for(int i = 0; i < M; i++) {
		cin >> s;
		for(int j = 1; j < s.size(); j++) {
			int a = s[j - 1] - 65, b = s[j] - 65;
			if(!g[a][b]) g[a][b] = true, deg[b]++, e++;
		}
	}
	if(e + 1 == sum) {
		for(int i = 0; i < 26; i++) {
			if(deg[i] == 0 && ap[i]) dfs(i);
		}
		cout << ret << endl;
	}
	else cout << -1 << endl;
	return 0;
}