#include "bits/stdc++.h"
#define REP(i,n,N) for(ll i=(n); i<(N); i++)
#define RREP(i,n,N) for(ll i=(N-1); i>=n; i--)
#define CK(n,a,b) ((a)<=(n)&&(n)<(b))
#define ALL(v) (v).begin(),(v).end()
#define p(s) cout<<(s)<<endl
#define p2(a,b) cout<<(a)<<" "<<(b)<<endl
#define v2(T) vector<vector<T>>
typedef long long ll;
using namespace std;
const ll inf=1e18;
const ll NODE_SIZE = 60;


int N, M;
map<char,char> mp;
int main(){
    cin>>N;
    vector<char> start;
    int size=0;
    REP(i,0,N){
        string s;
        cin>>s;
        size+=s.size();
        start.push_back(s[0]);
        REP(j,0,s.size()-1){
            mp[s[j]] = s[j+1];
        }
    }
    cin>>M;
    REP(i,0,M){
        string s;
        cin>>s;
        start.push_back(s[0]);
        REP(j,0,s.size()-1){
            mp[s[j]] = s[j+1];
        }
    }
    sort(ALL(start));
    start.erase(unique(ALL(start)), start.end());
    for(auto c:start){
        string s;
        char now = c;
        s += now;
        while(mp.find(now) != mp.end()){
            now = mp[now];
            s += now;
        }
        if(s.size()==size){
            p(s);
            return 0;
        }
    }
    p(-1);

    return 0;
}