N = int(input())
A = list(map(int, input().split(' ')))
M = int(input())
B = list(map(int, input().split(' ')))

put = [0 for _ in range(N)]
used = [0 for _ in range(M)]
A = sorted(A, reverse=True)
B = sorted(B, reverse=True)

for i in range(M):
    for j in range(N):
        if put[j] == 0:
            if 0 <= B[i] - A[j]:
                B[i] = B[i] - A[j]
                put[j] = 1
                used[i] = 1
                
if sum(put) == N:
    for i in range(M):
        if (i < M-1 and used[i+1] == 0) or (i == M-1 and used[i] == 1):
            print(i+1)
            exit(0)
else:
    print(-1)