N = int(input())
A = [input().strip() for _  in range(N)]
M = int(input())
B = [input().strip() for _ in range(M)]
F = {}
G = {}
for block in A:
    for a in block:
        F[a] = "0"
        G[a] = "0"
for block in A:
    for i in range(1,len(block)):
        F[block[i-1]] = block[i]
        G[block[i]] = block[i-1]
for block in B:
    for i in range(1,len(block)):
        F[block[i-1]] = block[i]
        G[block[i]] = block[i-1]
for a in G:
    if G[a]=="0":
        s = a
        break
ans = s
a = s
while F[a]!="0":
    t = F[a]
    ans += t
    a = t
if len(ans)==len(F):
    print(ans)
else:
    print(-1)