#include <bits/stdc++.h>
using namespace std;

int main(){
	int N;
	cin >> N;
	vector<int> A(N);
	vector<int> B(N);

	for(int i=0; i<N; i++) cin >> A[i];
	for(int i=0; i<N; i++) cin >> B[i];

	string numA = "0123";
	string numB = "0123";
	double win = 0;
	double cnt = 0;
	do{
		do{
			cnt+=1;
			int w = 0;
			for(int i=0; i<N; i++){
				int indA = numA[i] - '0';
				int indB = numB[i] - '0';
				if(A[indA] > B[indB]) w++;
			}

			if(w > N/2) win+=1;

		} while(next_permutation(numB.begin(),numB.begin()+N));
	} while(next_permutation(numA.begin(),numA.begin()+N));

	cout << win/cnt << endl;
}