#include "bits/stdc++.h"
#define ALL(obj) (obj).begin(),(obj).end()
#define RALL(obj) (obj).rbegin(),(obj).rend()
#define REP(i, n) for(int i = 0; i < (int)(n); i++)
#define REPR(i, n) for(int i = (int)(n); i >= 0; i--)
#define FOR(i,n,m) for(int i = (int)(n); i < int(m); i++)
using namespace std;
typedef long long ll;
const int MOD = 1e9 + 7;
const int INF = MOD - 1;
const ll LLINF = 4e18;

int main() {
    int n, m; cin >> n;
    vector<int> left(26, -1),right(26,-1);
    vector<bool> exist(26, false);
    REP(i, n) {
        string s; cin >> s;
        REP(j, s.size()) {
            int c = s[j] - 'A';
            exist[c] = true;
            if (j < s.size() - 1) right[c] = s[j + 1] - 'A';
            if (j > 0) left[c] = s[j - 1] - 'A';
        }
    }
    cin >> m;
    REP(i, m) {
        string s; cin >> s;
        REP(j, s.size()) {
            int c = s[j] - 'A';
            if (!exist[c]) {
                puts("-1");
                return 0;
            }
            if (j < s.size() - 1) right[c] = s[j + 1] - 'A';
            if (j > 0) left[c] = s[j - 1] - 'A';
        }
    }
    int k,cnt=0;
    REP(i, 26) {
        if (exist[i]) {
            if (left[i] == -1) {
                k = i;
            }
            cnt++;
        }
    }
    vector<char> ans;
    while (k != -1) {
        ans.push_back(char('A' + k));
        k = right[k];
        cnt--;
    }
    if (cnt == 0) {
        REP(i, ans.size()) {
            cout << ans[i];
        }
        cout << endl;
    }
    else {
        puts("-1");
    }
    getchar(); getchar();
}