n=int(input())
A=list(map(int,input().split()))
B=list(map(int,input().split()))

mod = 10**9+7

kouho=[]
ones=[]
for i in range(n):
    a,b=A[i],B[i]
    if b==1:
        ones.append(a)
    else:
        kouho.append((a/(1-b), a,b))

kouho.sort(reverse=True)
level=1
ans=0
for _,a,b in kouho:
    ans+=a*level%mod
    ans%=mod
    level*=b
    level%=mod
for a in ans:
    ans+=a*level%mod
    ans%=mod
    
print(ans)