n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
c=[i for i in range(n)];v=10**12
c.sort(key=lambda x:(b[x]-1)*v//a[x],reverse=True)
mod=10**9+7
ans,level=0,1
for i in c:
    ans+=level*a[i]
    level*=b[i]
    ans%=mod
    level%=mod
print(ans)