#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize("O3")


#define rep(i,n) for(ll i=0;i<n;i++)
#define repl(i,l,r) for(ll i=(l);i<(r);i++)
#define per(i,n) for(ll i=(n)-1;i>=0;i--)
#define perl(i,r,l) for(ll i=r-1;i>=l;i--)
#define fi first
#define se second
#define ins insert
#define pqueue(x) priority_queue<x,vector<x>,greater<x>>
#define all(x) (x).begin(),(x).end()
#define CST(x) cout<<fixed<<setprecision(x)
#define rev(x) reverse(x);
using ll=long long;
using vl=vector<ll>;
using vvl=vector<vector<ll>>;
using pl=pair<ll,ll>;
using vpl=vector<pl>;
using vvpl=vector<vpl>;
const ll MOD=1000000007;
const ll MOD9=998244353;
const int inf=1e9+10;
const ll INF=4e18;
const ll dy[9]={1,0,-1,0,1,1,-1,-1,0};
const ll dx[9]={0,1,0,-1,1,-1,1,-1,0};
template <typename T> inline bool chmax(T &a, T b) {
  return ((a < b) ? (a = b, true) : (false));
}
template <typename T> inline bool chmin(T &a, T b) {
  return ((a > b) ? (a = b, true) : (false));
}

int main(){
  vl v(26,-1);
  vl seen(26);
  ll n;cin >> n;
  ll sum=0;
  rep(i,n){
    string s;cin >> s;
    sum+=s.size();
    rep(j,s.size())seen[s[j]-'A']++;
    rep(j,s.size()-1){
      v[s[j]-'A']=s[j+1]-'A';
    }
  }
  ll m;cin >> m;
  rep(i,m){
    string s;cin >> s;
    rep(j,s.size()-1){
      v[s[j]-'A']=s[j+1]-'A';
    }
  }
  rep(i,26){
    if(!seen[i])continue;
    string ans;
    ll now=i;
    while(now!=-1){
      ans+='A'+now;
      now=v[now];
    }
    if(sum==ans.size()){
      cout << ans << endl;return 0;
    }
  }
  cout << -1 << endl;

}