using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Globalization;
using System.Diagnostics;
using static System.Console;
using Pair = System.Collections.Generic.KeyValuePair<int, int>;
//using System.Numerics;

class Program
{
    static void Main()
    {
        //SetOut(new StreamWriter(OpenStandardOutput()) { AutoFlush = false });
        new Program().Solve();
        Out.Flush();
    }
    Scanner cin = new Scanner();
    Random rnd = new Random();
    Stopwatch sw = new Stopwatch();
    readonly int[] dd = { 0, 1, 0, -1, 0 };
    readonly int mod = 1000000007;
    readonly string alfa = "abcdefghijklmnopqrstuvwxyz";


    void Solve()
    {

        int N = cin.Nextint;
        int M = N / 2;
        var P = new Pair[N / 2];
        var F = new int[N, N];
        for (int i = 0; i < N; i++)
        {
            for (int j = 0; j < N; j++)
            {
                F[i, j] = cin.Nextint;
            }
        }
        //となり同士をつなぐ
        int ans = 0;
        for (int i = 0; i < N; i+=2)
        {
            P[i / 2] = new Pair(i, i + 1);
            ans += F[i, i + 1];
        }

        
        sw.Start();
        while (sw.ElapsedMilliseconds < 900)
        {

            //ペアを２個づつ抜き出す
            for (int i = 0; i < M; i++)
            {
                for (int j = i + 1; j < M; j++)
                {
                    int a = P[i].Key, b = P[i].Value, c = P[j].Key, d = P[j].Value;
                    int now = F[a, b] + F[c, d];
                    int one = F[a, c] + F[b, d];
                    int two = F[a, d] + F[b, c];

                    if (one > now && one >= two)
                    {
                        P[i] = new Pair(a, c);
                        P[j] = new Pair(b, d);
                        int cnt = 0;
                        foreach (var v in P)
                        {
                            cnt += F[v.Key, v.Value];
                        }
                        ans = Math.Max(ans, cnt);
                    }
                    else if (two > now && two > one)
                    {
                        P[i] = new Pair(a, d);
                        P[j] = new Pair(b, c);
                        int cnt = 0;
                        foreach (var v in P)
                        {
                            cnt += F[v.Key, v.Value];
                        }
                        ans = Math.Max(ans, cnt);
                    }
                }
            }
            
        }

   
        WriteLine(ans);

    }

}

class Scanner
{
    string[] s; int i;
    char[] cs = new char[] { ' ' };
    public Scanner() { s = new string[0]; i = 0; }
    public string[] Scan { get { return ReadLine().Split(); } }
    public int[] Scanint { get { return Array.ConvertAll(Scan, int.Parse); } }
    public long[] Scanlong { get { return Array.ConvertAll(Scan, long.Parse); } }
    public double[] Scandouble { get { return Array.ConvertAll(Scan, double.Parse); } }
    public string Next
    {
        get
        {
            if (i < s.Length) return s[i++];
            string st = ReadLine();
            while (st == "") st = ReadLine();
            s = st.Split(cs, StringSplitOptions.RemoveEmptyEntries);
            i = 0;
            return Next;
        }
    }
    public int Nextint { get { return int.Parse(Next); } }
    public long Nextlong { get { return long.Parse(Next); } }
    public double Nextdouble { get { return double.Parse(Next); } }
}