#include <bits/stdc++.h>
#define ALL(A) (A).begin(), (A).end()
#define ll long long
#define rep(i, n) for (int i = 0; i < (n); i++)

using namespace std;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }

const ll mod = 1e9 + 7;
const ll INF = -1 * ((1LL << 63) + 1);
const int inf = -1 * ((1 << 31) + 1);
int n;
int used[5];
vector<int> a(5);
vector<int> b(5);
double win,lose,draw;
vector<vector<int>> pa,pb;
void dfs(int d,vector<int> c,vector<int> &a,vector<vector<int>> &pa){
    if(d==n){
        pa.push_back(c);
        return;
    }
    rep(i,n){
        if(used[i])continue;
        used[i] = 1;
        c.push_back(a[i]);
        dfs(d+1,c,a,pa);
        c.pop_back();
        used[i] = 0;
    }
}

int main(void){
    cin.tie(0);
    ios::sync_with_stdio(false);
    cout << fixed << setprecision(20);
    cin >> n;
    rep(i,n)cin >> a[i];
    rep(i,n)cin >> b[i];
    rep(i,n){
        vector<int>c;
        used[i] = 1;
        c.push_back(a[i]);
        dfs(1,c,a,pa);
        c.pop_back();
        used[i] = 0;
    }
    rep(i,n){
        vector<int>c;
        used[i] = 1;
        c.push_back(b[i]);
        dfs(1,c,b,pb);
        c.pop_back();
        used[i] = 0;
    }
    for(int i=0;i<pa.size();i++){
        for(int j=0;j<pb.size();j++){
            int aw = 0,bw = 0;
            for(int k=0;k<n;k++){
                if(pa[i][k]>pb[j][k])aw++;
                else bw++;
            }
            if(aw>bw)win++;
            else if(aw==bw)draw++;
            else lose++;
        }
    }
    cout << (win)/(win+draw+lose) << endl;
}