import itertools

N = int(input())
A = sorted(list(map(int, input().split())))
M = int(input())
B = sorted(list(map(int, input().split())), reverse=True)

for i, b in enumerate(B, 1):
    max_b = 0
    max_Ac = 0
    tmp = tuple([0] * len(A))
    it = itertools.product((0, 1), repeat=len(A))
    next(it)
    for t in it:
        A_c = tuple(itertools.compress(A, t))
        if max_b <= sum(A_c) <= b and max_Ac <= max(A_c):
            max_b = sum(A_c)
            max_Ac = max(A_c)
            tmp = t
    A = list(itertools.compress(A, (not x for x in tmp)))
    if not A:
        print(i)
        break
else:
    print(-1)