#define _USE_MATH_DEFINES
#include <algorithm>
#include <cstdio>
#include <functional>
#include <iostream>
#include <cfloat>
#include <climits>
#include <cstring>
#include <cmath>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
struct edge { int u, v; ll w; };

ll MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;

int main() {
	int N; cin >> N;
	vector<int> A(N), B(N);
	for (int i = 0; i < N; i++)
		cin >> A[i];
	for (int i = 0; i < N; i++)
		cin >> B[i];
	int win = 0;
	for (int t = 0; t < 24; t++) {
		int cnt = 0;
		for (int i = 0; i < N; i++)
			if (A[i] > B[i])
				cnt++;
		if (cnt > N / 2) win++;
		next_permutation(A.begin(), A.end());
	}
	cout << win / 24.0 << endl;
}