N = int(input())
A = list(map(int,input().split()))
M = int(input())
B = list(map(int,input().split()))
A.sort(reverse=True)
B.sort(reverse=True)
ans = 100
for bit in range(1,2**M):
    C = []
    x = bit
    for i in range(M):
        if x & 1:
            C.append(B[i])
        x >>= 1
    flg = True
    for i in range(N):
        flg2 = True
        for j in range(len(C)):
            if A[i] <= C[j]:
                C[j] -= A[i]
                flg2 = False
                break
        if flg2:
            flg = False
            break
    if flg:
        ans = min(ans, len(C))
if ans == 100:
    ans = -1
print(ans)