import sys

sys.setrecursionlimit(10 ** 6)
def LI(): return list(map(int, sys.stdin.readline().split()))

from random import *
def main():
    def game(xx,yy):
        sx=sy=0
        for _ in range(n-1):
            m = len(xx)
            if randrange(1000) < pa: i = m-1
            else: i = randrange(m-1)
            if randrange(1000) < pb: j = m-1
            else: j = randrange(m-1)
            if xx[i]>yy[j]:sx+=xx[i]+yy[j]
            else:sy+=xx[i]+yy[j]
            del xx[i]
            del yy[j]
        if xx[0]>yy[0]:return sx+xx[0]+yy[0]>sy
        else:return sx>sy+xx[0]+yy[0]
        #print(xx,yy,m,i,j)

    n,pa,pb=input().split()
    n=int(n)
    pa=int(pa[2:])
    pb=int(pb[2:])
    aa=LI()
    bb=LI()
    aa.sort(reverse=True)
    bb.sort(reverse=True)
    loop=100000
    win=0
    for _ in range(loop):
        if game(aa[:],bb[:]):win+=1
    print(win/loop)


main()