import bisect import copy import decimal import fractions import functools import heapq import itertools import math import random import sys from collections import Counter,deque,defaultdict from functools import lru_cache,reduce from heapq import heappush,heappop,heapify,heappushpop,_heappop_max,_heapify_max def _heappush_max(heap,item): heap.append(item) heapq._siftdown_max(heap, 0, len(heap)-1) def _heappushpop_max(heap, item): if heap and item < heap[0]: item, heap[0] = heap[0], item heapq._siftup_max(heap, 0) return item from math import gcd as GCD read=sys.stdin.read readline=sys.stdin.readline readlines=sys.stdin.readlines N=int(readline()) P=list(map(int,readline().split())) Q=list(map(int,readline().split())) for i in range(N): P[i]=(P[i]*Q[i]/100000,Q[i]/100) _heapify_max(P) ans=0 pro=1 for _ in range(10**6): p,q=_heappop_max(P) ans+=pro pro-=p _heappush_max(P,(p*(1-q),q)) print(ans)