from heapq import heappop,heappush

n=int(input())
P=list(map(int,input().split()))
Q=list(map(int,input().split()))

X=[]
for i in range(n):
    X.append((-P[i]*Q[i]/100000,1-Q[i]/100))

X.sort()

ANS=0
for tests in range(1,9999):
    x,y=heappop(X)

    ANS+=-x*tests
    heappush(X,(x*y,y))

print(ANS)