import java.util.*;
import java.io.*;

public class Main {
	public static void main (String[] args) throws Exception {
	    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
	    int n = Integer.parseInt(br.readLine());
	    int[] next = new int[26];
	    int size = 0;
	    Arrays.fill(next, -1);
	    HashSet<Integer> starts = new HashSet<>();
	    for (int i = 0; i < n; i++) {
	        char[] arr = br.readLine().toCharArray();
	        size += arr.length;
	        for (int j = 0; j < arr.length - 1; j++) {
                next[arr[j] - 'A'] = arr[j + 1] - 'A';
	        }
	        starts.add(arr[0] - 'A');
	    }
	    int m = Integer.parseInt(br.readLine());
	    for (int i = 0; i < m; i++) {
	        char[] arr = br.readLine().toCharArray();
	        for (int j = 0; j < arr.length - 1; j++) {
                next[arr[j] - 'A'] = arr[j + 1] - 'A';
	        }
	    }
	    for (int x : starts) {
	        StringBuilder sb = new StringBuilder();
	        sb.append((char)(x + 'A'));
	        while (next[x] != -1) {
	            x = next[x];
	            sb.append((char)(x + 'A'));
	        }
	        if (sb.length() == size) {
	            System.out.println(sb);
	            return;
	        }
	    }
	    System.out.println(-1);
    }
}