import itertools
import copy
N = int(input())
lsA = list(map(int,input().split()))
M = int(input())
lsB = list(map(int,input().split()))
lsB.sort(reverse=True)

lsp = itertools.permutations(lsA)

cnt = float('INF')
for p in lsp:
    lsB1 = copy.copy(lsB)
    for i in range(N):
        f = False
        for j in range(M):
            if lsB1[j] >= p[i]:
                lsB1[j] -= p[i]
                f = True
                break
        if f == False:
            break
    if f:
        ii = 0
        for j in range(M):
            if lsB1[j] != lsB[j]:
                ii += 1
        cnt = min(ii,cnt)

if cnt == float('INF'):
    print(-1)
else:
    print(cnt)