input()
W = set(map(int, input().split()))
input()
B = set(map(int, input().split()))

w, b, cnt = 1, 1, 0

for x in sorted(list(W|B)):
	if x in W&B:
		cnt += 1
		w, b = b, w
	elif b*x in W:
		cnt += 1
		w, b = 1, 0
	elif w*x in B:
		cnt += 1
		w, b = 0, 1

print(cnt)