#include <bits/stdc++.h>
using namespace std;
int main(void){
    // Your code here!
    int N;
    cin >> N;
    vector<int> A(N);
    vector<int> B(N);
    for(int i = 0; i < N; i++)cin >> A.at(i);
    for(int i = 0; i < N; i++)cin >> B.at(i);
    if(N == 1){
        if(A.at(0) > B.at(0)){
            cout << 1;
        }
        else{
            cout << 0;
        }
    }
    if(N == 2){
        int ans = 0;
        if(A.at(0) > B.at(0) && A.at(1) > B.at(1)){
            ans ++;
        }
        if(A.at(0) > B.at(1) && A.at(1) > B.at(0)){
            ans ++;
        }
        cout << 1. * ans / 2;
    }
    if(N == 3){
        int ans = 0;
        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                for(int k = 0; k < N; k++){
                    int l = 0;
                    if(i != j && i != k && j != k){
                        if(A.at(i) > B.at(0))l++;
                        if(A.at(j) > B.at(1))l++;
                        if(A.at(k) > B.at(2))l++;
                    }
                    if(l >= 2)ans++;
                }
            }
        }
        cout << 1. * ans / 6;
    }
    if(N == 4){
        int ans = 0;
        for(int i = 0; i < N; i++){
            for(int j = 0; j < N; j++){
                for(int k = 0; k < N; k++){
                    for(int l = 0; l < N; l++){
                        int m = 0;
                        if(i != j && i != k && i != l && j != k && j != l && k != l){
                            if(A.at(i) > B.at(0))m++;
                            if(A.at(j) > B.at(1))m++;
                            if(A.at(k) > B.at(2))m++;
                            if(A.at(l) > B.at(3))m++;
                        }
                        if(m >= 3)ans++;
                        
                    }
                }
            }
        }
        cout << 1. * ans / 24;
    }
}