from bisect import *
from math import *
from collections import *
from heapq import *
from random import *
import sys

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def II(): return int(sys.stdin.readline())
def MI(): return map(int, sys.stdin.readline().split())
def MF(): return map(float, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LF(): return list(map(float, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    n=II()
    aa=LI()
    bb=LI()
    game_win=0
    sample_number=1000000//n
    for _ in range(sample_number):
        turn_win=0
        rand_aa=sample(aa,n)
        rand_bb=sample(bb,n)
        for a,b in zip(rand_aa,rand_bb):
            if a>b:turn_win+=1
        if turn_win*2>n:game_win+=1
    print(game_win/sample_number)

main()