import itertools
N = int(input())

a = list(map(int, input().split()))
b = list(map(int, input().split()))

per1 = itertools.permutations(list(range(N)), N)
per2 = itertools.permutations(list(range(N)), N)
cnt = 0
count = 0
c = 0

for xx in per2:
    for x in xx:
        for yy in per1:
            cnt = 0
            for y in yy:
                if a[x]>b[y]:
                    cnt += 1
            c += 1

            if cnt > N/2:
                count += 1


else:
    ans = cnt / c
    print(ans)