#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <queue>
#include <string>
#include <map>
#include <set>
#include <stack>
#include <tuple>
#include <deque>
#include <array>
#include <numeric>
#include <bitset>
#include <iomanip>
#include <cassert>
#include <chrono>
#include <random>
#include <limits>
#include <iterator>
#include <functional>
#include <sstream>
#include <fstream>
#include <complex>
#include <cstring>
#include <unordered_map>
using namespace std;

using ll = long long;
using P = pair<int, int>;
constexpr int INF = 1001001001;
constexpr int mod = 1000000007;
// constexpr int mod = 998244353;

template<class T>
inline bool chmax(T& x, T y){
    if(x < y){
        x = y;
        return true;
    }
    return false;
}
template<class T>
inline bool chmin(T& x, T y){
    if(x > y){
        x = y;
        return true;
    }
    return false;
}

int f[26], indeg[26], g[26][26];

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

    int N, M;
    string s;
    cin >> N;
    for(int i = 0; i < N; ++i){
        cin >> s;
        int n = s.length();
        for(int j = 0; j < n; ++j){
            f[s[j] - 'A'] = 1;
            if(j == n - 1)  continue;
            g[s[j] - 'A'][s[j + 1] - 'A'] = 1;
        }
    }
    cin >> M;
    for(int i = 0; i < M; ++i){
        cin >> s;
        int n = s.length();
        for(int j = 0; j < n; ++j){
            f[s[j] - 'A'] = 1;
            if(j == n - 1)  continue;
            g[s[j] - 'A'][s[j + 1] - 'A'] = 1;
        }
    }

    for(int i = 0; i < 26; ++i){
        for(int j = 0; j < 26; ++j){
            if(g[i][j]) indeg[j] += 1;
        }
    }

    queue<int> que;
    for(int i = 0; i < 26; ++i){
        if(f[i] && !indeg[i])   que.emplace(i);
    }
    vector<int> ord;
    while(!que.empty()){
        int u = que.front();
        que.pop();
        ord.emplace_back(u);
        for(int v = 0; v < 26; ++v){
            if(g[u][v] && --indeg[v] == 0)  que.emplace(v);
        }
    }

    int n = ord.size();
    for(int i = 1; i < n; ++i){
        bool ok = false;
        for(int j = 0; j < 26; ++j){
            if(g[j][ord[i]])    ok = true;
        }
        if(!ok){
            cout << -1 << endl;
            return 0;
        }
    }

    for(int i : ord)    cout << (char)('A' + i);
    cout << endl;

    return 0;
}