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

int cnt = 0;
map<char, int> toint;
map<int, char> tochar;

int main() {
    int n;
    cin >> n;
    vector<string> vs;
    for (int i = 0; i < n; i++) {
        string s;
        cin >> s;
        for (char c: s) {
            assert(toint.count(c) == 0);
            toint[c] = cnt++;
            tochar[toint[c]] = c;
        }
        vs.push_back(s);
    }

    vector<vector<int>> adj(cnt, vector<int>(cnt));
    for (string& s: vs) {
        if (s.size() > 1) {
            for (int i = 1; i < s.size(); i++) {
                adj[toint[s[i - 1]]][toint[s[i]]] = 1;
            }
        }
    }

    cin >> n;
    for (int i = 0; i < n; i++) {
        string s;
        cin >> s;
        if (s.size() > 1) {
            for (int i = 1; i < s.size(); i++) {
                assert(toint.count(s[i - 1]) && toint.count(s[i]));
                adj[toint[s[i - 1]]][toint[s[i]]] = 1;
            }
        }
    }

    for (int i = 0; i < cnt; i++) {
        int s = 0;
        for (int j = 0; j < cnt; j++) {
            s += adj[i][j];
        }
        assert(s <= 1);
    }

    for (int i = 0; i < cnt; i++) {
        string ans = "";
        int crt = i;
        while (1) {
            ans += tochar[crt];
            bool hasnext = false;
            for (int j = 0; j < cnt; j++) {
                if (adj[crt][j]) {
                    crt = j;
                    hasnext = true;
                    break;
                }
            }
            if (!hasnext) {
                break;
            }
        }
        if (ans.size() == cnt) {
            cout << ans << endl;
            return 0;
        }
    }
    cout << -1 << endl;
}