#include <algorithm>
#include <iostream>
#include <stack>
#include <vector>
using namespace std;

vector<bool> have;

int tour(const vector<vector<int>> &g, vector<int> *path, size_t len) {
  int n = static_cast<int>(g.size());
  vector<int> indeg(n), utdeg(n);
  for(int u=0; u<n; ++u) {
    for(int v : g[u]) {
      ++indeg[v];
      ++utdeg[u];
    }
  }
  int k = n;
  for(int v=0; v<n; ++v) {
    if(indeg[v] == utdeg[v]) { --k; }
  }
  for(int u=0; u<n; ++u) {
    if(!have[u]) { continue; }
    if(k == 0 || (k == 2 && utdeg[u]-indeg[u] == 1)) {
      *path = vector<int>();
      stack<int> stk;
      stk.push(u);
      vector<size_t> idx(n);
      while(!stk.empty()) {
        int v = stk.top(); stk.pop();
        while(idx[v] < g[v].size()) {
          stk.push(v);
          v = g[v][idx[v]++];
        }
        path->push_back(v);
      }
      if(path->size() == len) {
        return 1 + (k == 0);
      }
    }
  }
  return 0;
}

int main(void) {
  int N; cin >> N;
  vector<int> nxt(26, -1);
  have.assign(26, false);
  vector<vector<int>> G(26, vector<int>());
  size_t len = 0;
  for(int loop=0; loop<N; ++loop) {
    string s; cin >> s;
    len += s.size();
    for(int i=0, n=static_cast<int>(s.size()); i<n-1; ++i) {
      int u = s[i]   - 'A',
          v = s[i+1] - 'A';
      nxt[u] = v;
      have[u] = true;
      G[u].push_back(v);
    }
    have[s.back() - 'A'] = true;
  }
  int M; cin >> M;
  for(int loop=0; loop<M; ++loop) {
    string s; cin >> s;
    for(int i=0, n=static_cast<int>(s.size()); i<n-1; ++i) {
      int u = s[i]   - 'A',
          v = s[i+1] - 'A';
      if(nxt[u] == -1) {
        G[u].push_back(v);
      }
    }
  }
  vector<int> path;
  int state = tour(G, &path, len);
  if(!state) {
    puts("-1");
    return 0;
  }
  reverse(path.begin(), path.end());
  string res;
  for(int vi : path) { res += static_cast<char>(vi + 'A'); }
  cout << res << '\n';
  return 0;
}