from collections import deque
def cycle_detectable_topological_sort(g, ind):
    V = len(g)
    order = []
    depth = [-1]*V
    for i in range(V):
        if not ind[i]:
            order.append(i)
            depth[i] = 0

    q = deque(order)
    while q:
        v = q.popleft()
        cur_depth = depth[v]
        for u in g[v]:
            ind[u] -= 1
            if not ind[u]:
                depth[u] = max(depth[u], cur_depth+1)
                q.append(u)
                order.append(u)
    if len(order) == V:
        return (order, depth)
    else:
        return (None, None)

n = int(input())
A = [str(input()) for i in range(n)]
m = int(input())
B = [str(input()) for i in range(m)]

g = [[] for i in range(26)]
ind = [0]*26
E = set()
for a in A:
    for i in range(len(a)-1):
        c1 = ord(a[i])-ord('A')
        c2 = ord(a[i+1])-ord('A')
        g[c1].append(c2)
        ind[c2] += 1
        E.add((c1, c2))
for b in B:
    for i in range(len(b)-1):
        c1 = ord(b[i])-ord('A')
        c2 = ord(b[i+1])-ord('A')
        g[c1].append(c2)
        ind[c2] += 1
        E.add((c1, c2))

order, _  = cycle_detectable_topological_sort(g, ind)
used = set()
for a in A:
    for c in a:
        c = ord(c)-ord('A')
        used.add(c)
for b in B:
    for c in b:
        c = ord(c)-ord('A')
        used.add(c)
order = [i for i in order if i in used]
for k in range(len(order)-1):
    c1 = order[k]
    c2 = order[k+1]
    if (c1, c2) not in E:
        print(-1)
        exit()
else:
    ans = [chr(i+ord('A')) for i in order]
    print(''.join(ans))