using System;
using System.Collections.Generic;
using System.Linq;
using System.Collections;
using System.Linq.Expressions;

static class Program
{
    static void Main()
    {
        new Magatro().Solve();
    }
}

struct P
{
    public string Name;
    public int Time;
    public P(string s, int time)
    {
        Name = s;
        Time = time;
    }
}

class Magatro
{
    private int N;
    private int[][] F;
    private int[] M = (new int[1 << 24]).Select(i => -1).ToArray();
    private void Scan()
    {
        N = int.Parse(Console.ReadLine());
        F = new int[N][];
        for (int i = 0; i < N; i++)
        {
            F[i] = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();
        }
    }

    public int Sol(int use)
    {
        if (M[use] != -1)
        {
            return M[use];
        }
        int first = -1;
        for (int i = 0; i < N; i++)
        {
            int j = 1 << i;
            if ((use & j) == 0)
            {
                first = i;
                break;
            }
        }
        if (first == -1)
        {
            return 0;
        }
        use += 1 << first;
        int max = -1;
        for (int second = first + 1; second < N; second++)
        {
            int j = 1 << second;
            if ((use & j) == 0)
            {
                use += 1 << second;
                var i = Sol(use) + F[first][second];
                if (max < i)
                {
                    max = i;
                }
                use -= 1 << second;
            }
        }
        use -= 1 << first;
        M[use] = max;
        return max;
    }

    public void Solve()
    {
        Scan();
        Console.WriteLine(Sol(0));
    }

}