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

#define FOR(i,a,b) for (int i = (a); i < (b); i++)
#define RFOR(i,b,a) for (int i = (b)-1; i >= (a); i--)
#define ITER(it,a) for (__typeof(a.begin()) it = a.begin(); it != a.end(); it++)
#define FILL(a,value) memset(a, value, sizeof(a))

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair

typedef long long LL;
typedef vector<int> VI;
typedef pair<int, int> PII;

const double PI = acos(-1.0);
const int INF = 1000 * 1000 * 1000 + 7;
const LL LINF = INF * (LL) INF;

const int MAX = 3030;

double P[3][MAX];
int n;

bool U[MAX];
bool W[MAX];

int findMax()
{
    pair<double, int> mx = MP(-1e47, -INF);

    FOR (i, 0, n * 3)
    {
        if (U[i]) continue;

        mx = max(mx, MP(P[2][i], i));
    }

    return mx.second;
}

int main()
{
    freopen("in.txt", "r", stdin);
    //ios::sync_with_stdio(false); cin.tie(0);

    cin>>n;

    FOR (i, 0, 3)
    {
        FOR (j, 0, n * 3)
        {
            cin>>P[i][j];
        }
    }

    double sum = 0;
    FOR (j, 0, n * 3)
    {
        sum += P[1][j];
        P[2][j] -= P[1][j];
    }

    FOR (j, 0, n)
    {
        int ind = findMax();
        U[ind] = true;
        sum += P[2][ind];
    }

    sum = -sum;

    FOR (it, 0, n)
    {
        int ind = findMax();

        pair<double, int> mx = MP(-1e47, -INF);

        FOR (i, 0, n * 3)
        {
            if (W[i]) continue;

            double cur = P[0][i] * 2 + P[1][i];
            if (U[i])
            {
                cur += P[2][i];
                cur -= P[2][ind];
            }

            mx = max(mx, MP(cur, i));
        }

        sum += mx.first;
        W[mx.second] = true;
        if (U[mx.second]) U[ind] = true;
    }

    sum /= 3;

    printf("%.11f\n", sum);

}