#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<cstdio>
#include<sstream>
#include<iomanip>
#include<assert.h>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define all(in) in.begin(),in.end()
#define shosu(x) fixed<<setprecision(x)
using namespace std;
//kaewasuretyuui
typedef long long ll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pii> vp;
typedef vector<vp> vvp;
typedef vector<string> vs;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef pair<int,pii> pip;
typedef vector<pip>vip;
const double PI=acos(-1);
const double EPS=1e-7;
const int inf=1e8;
const ll INF=1e16;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};
vi used(26);
int G[26][26];
int co[2][26];
int co1,co2,h;
void dfs(int a,int b,string s){
	if(b+1==co2){
		h=true;
		cout<<s<<endl;
		return;
	}
	rep(i,26)if(G[a][i]&&used[i]==0){
		used[i]=true;
		dfs(i,b+1,s+(char)(i+'A'));
		used[i]=false;
	}
}
int main(){
	rep(q,2){
		int a;
		cin>>a;
		assert(1<=a&&a<=26);
		while(a--){
			string s;cin>>s;
			rep(i,s.size()-1)G[s[i]-'A'][s[i+1]-'A']=1;
			rep(i,s.size())co[q][s[i]-'A']++;
			rep(i,s.size())assert('A'<=s[i]&&s[i]<='Z');
		}
	}
	rep(i,26)assert(co[0][i]<2&&co[1][i]<2&&co[0][i]==co[1][i]);
	rep(i,26)rep(j,26)co1+=G[i][j];
	rep(i,26)co2+=co[0][i];
	if(co1+1!=co2){
		cout<<-1<<endl;
		return 0;
	}
	rep(i,26)if(co[0][i]){
		used=vi(26);
		used[i]=true;
		string s="";
		dfs(i,0,s+(char)('A'+i));
	}
	if(!h)cout<<-1<<endl;
}