import random
from itertools import permutations

N = int(input())
A = list(map(int, input().split()))
B = list(map(int, input().split()))


def judge(xs, ys):
    win = 0
    for x, y in zip(xs, ys):
        if x > y:
            win += 1
        else:
            win -= 1

    return win > 0


trials = 1_000_000
win = 0
for _ in range(trials):
    a = A[:]
    b = B[:]
    random.shuffle(a)
    random.shuffle(b)

    if judge(a, b):
        win += 1

ans = win / trials
print(ans)