#include "bits/stdc++.h"
using namespace std;
#define FOR(i,j,k) for(int (i)=(j);(i)<(int)(k);++(i))
#define rep(i,j) FOR(i,0,j)
#define each(x,y) for(auto &(x):(y))
#define mp make_pair
#define mt make_tuple
#define all(x) (x).begin(),(x).end()
#define debug(x) cout<<#x<<": "<<(x)<<endl
#define smax(x,y) (x)=max((x),(y))
#define smin(x,y) (x)=min((x),(y))
#define MEM(x,y) memset((x),(y),sizeof (x))
#define sz(x) (int)(x).size()
#define pb push_back
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;

int N, M;
string s[26], t[26], ans = "-1";

void f(int S, int T, string x, string y) {
    rep(i, min(sz(x), sz(y))) {
        if (x[i] != y[i])return;
    }
    if ((S != 0 || T != 0) && sz(x) == sz(y) && sz(x) > 0) {
        cout << -1 << endl;
        exit(0);
    }
    if (S == 0 && T == 0) {
        ans = x;
        return;
    }

    if (sz(x) < sz(y)) {
        rep(i, N)if (S >> i & 1) {
            f(S ^ (1 << i), T, x + s[i], y);
        }
    } else {
        rep(i, M)if (T >> i & 1) {
            f(S, T ^ (1 << i), x, y + t[i]);
        }
    }
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> N; rep(i, N)cin >> s[i];
    cin >> M; rep(i, M)cin >> t[i];
    f((1 << N) - 1, (1 << M) - 1, "", "");
    cout << ans << endl;
}