#include <bits/stdc++.h>
using namespace std;
 
#define REP(i,n) for (int i=0,_n=(int)(n); i < _n; i++)
template<class T> bool chkmin(T &a, T b) { return a > b ? (a = b, true) : false; }
template<class T> bool chkmax(T &a, T b) { return a < b ? (a = b, true) : false; }

typedef long long ll;


bool g[30][30];
bool use[30];

int main2() {
  memset(g, 0, sizeof(g));
  memset(use, 0, sizeof(use));

  int N; cin >> N;
  REP(nnn, N) {
    string s; cin >> s;
    REP(i, s.size()) use[ s[i] - 'A'] = true;
    for (int i = 0; i + 1 < (int)s.size(); i++) {
      int a = s[i] - 'A';
      int b = s[i+1] - 'A';
      g[a][b] = true;
    }
  }
  int M; cin >> M;

  REP(mmm, M) {
    string s; cin >> s;
    REP(i, s.size()) use[ s[i] - 'A'] = true;

    for (int i = 0; i + 1 < (int)s.size(); i++) {
      int a = s[i] - 'A';
      int b = s[i+1] - 'A';
      g[a][b] = true;
    }
  }

  // REP(i, 26) if (use[i]) {
  //   REP(j, 26) if (use[j]) {
  //     cout << g[i][j];
  //   }
  //   cout << endl;
  // }

  int first = -1;
  for (int i = 0; i < 26; i++) if (use[i]) {
    int indeg = 0;
    REP(j, 26) if (use[j]) {
      if (g[j][i]) indeg++;
    }
    if (indeg == 0) {
      if (first != -1) { cout << -1 << endl; return 0; }
      first = i;
    }
  }
  string ans = "";
  int p = first;
  for (;;) {
    ans += (char)('A' + p);
    int next = -1;
    REP(j, 26) if (g[p][j]) { next = j; break; }
    if (next == -1) break;
    p = next;
  }
  cout << ans << endl;

  return 0;
}

int main() {
  for (;!cin.eof();cin>>ws) main2();
  return 0;
}