class UnionFind(object):
    def __init__(self, n=1):
        self.par = [i for i in range(n)]
        self.rank = [0 for _ in range(n)]
        self.size = [1 for _ in range(n)]

    def find(self, x):
        if self.par[x] == x:
            return x
        else:
            self.par[x] = self.find(self.par[x])
            return self.par[x]

    def union(self, x, y):
        x = self.find(x)
        y = self.find(y)
        if x != y:
            if self.rank[x] < self.rank[y]:
                x, y = y, x
            if self.rank[x] == self.rank[y]:
                self.rank[x] += 1
            self.par[y] = x
            self.size[x] += self.size[y]

    def is_same(self, x, y):
        return self.find(x) == self.find(y)

    def get_size(self, x):
        x = self.find(x)
        return self.size[x]

from heapq import *
def topsort(G):
    Q = []
    count = dict((u, 0) for u in range(len(G)))
 
    for u in range(len(G)):
        for v in G[u]:
            count[v] += 1
 
    temp = []
    for u in range(len(G)):
        if count[u] == 0:
            heappush(Q, u)
 
    anslst = []
    while Q:
        u = heappop(Q)
        anslst.append(u)
        temp = []
        for v in G[u]:
            count[v] -= 1
            if count[v] == 0:
                heappush(Q, v)
 
 
    anslst.reverse()
    return anslst

G = [[] for i in range(26)]
U = UnionFind(26)
N = int(input())
S = set()
for i in range(N):
    A = list(input())
    for a in A:
        S.add(a)
    for j in range(len(A) - 1):
        u, v = A[j:j+2]
        u, v = ord(u) - ord("A"), ord(v) - ord("A")
        G[u].append(v)
        U.union(u, v)

N = int(input())
for i in range(N):
    A = list(input())
    for a in A:
        S.add(a)
    for j in range(len(A) - 1):
        u, v = A[j:j+2]
        u, v = ord(u) - ord("A"), ord(v) - ord("A")
        if not G[u]:
            G[u].append(v)
        U.union(u, v)

L = topsort(G)
ans = []
for a in L:
    s = chr(a + ord("A"))
    if s in S:
        ans.append(s)
ans.reverse()
v = 0
for i in range(26):
    v = max(v, U.get_size(i))
if len(S) == len(ans) == v:
    print(*ans, sep="")
else:
    print(-1)