P = 10 ** 9 + 7
N = int(input())
X = sorted([(int(a), int(b)) for a, b in zip(input().split(), input().split())], key = lambda x: -(x[1] - 1) / x[0])
ans = 0
l = 1
for a, b in X:
    ans = (ans + l * a) % P
    l = l * b % P
print(ans)