import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        HashSet<Integer> starts = new HashSet<>();
        int[] next = new int[26];
        Arrays.fill(next, -1);
        boolean[] used = new boolean[26];
        for (int i = 0; i < n; i++) {
            char[] arr = sc.next().toCharArray();
            starts.add(arr[0] - 'A');
            used[arr[0] - 'A'] = true;
            for (int j = 0; j < arr.length - 1; j++) {
                next[arr[j] - 'A'] = arr[j + 1] - 'A';
                used[arr[j + 1] - 'A'] = true;
            }
        }
        int count = 0;
        for (boolean b : used) {
            if (b) {
                count++;
            }
        }
        int m = sc.nextInt();
        for (int i = 0; i < m; i++) {
            char[] arr = sc.next().toCharArray();
            starts.add(arr[0] - 'A');
            for (int j = 0; j < arr.length - 1; j++) {
                if (next[arr[j] - 'A'] >= 0 && next[arr[j] - 'A'] != arr[j + 1] - 'A') {
                    System.out.println(-1);
                    return;
                }
                next[arr[j] - 'A'] = arr[j + 1] - 'A';
            }
        }
        for (int x : starts) {
            int cur = x;
            int c = 0;
            StringBuilder sb = new StringBuilder();
            sb.append((char)(cur + 'A'));
            while (next[cur] >= 0) {
                cur = next[cur];
                sb.append((char)(cur + 'A'));
                c++;
            }
            if (c == count - 1) {
                System.out.println(sb);
                return;
            }
        }
        System.out.println(-1);
    }
}