using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using static System.Console;
using static System.Math;
using static MyIO;
using static MyUtil;
using static BinaryRepresentation;

public class U { public static void Main() => (new Solver()).Solve(); }

public class Solver
{
	public void Solve()
	{
		long N = GetLong();
		var a = new long[N, N];
		for(long i = 0; i < N; i++)
		{
			for(long j = 0; j < N; j++)
				a[i, j] = GetLong();
		}

		long U = leftShift(1, N);
		var sum = new long[U];
		for(long s = 0; s < U; s++)
		{
			for(long i = 0; i < N; i++)
			{
				if(!contains(s, i))
					continue;

				for(long j = 0; j < i; j++)
				{
					if(contains(s, j))
						sum[s] += a[i, j];
				}
			}
		}

		var dp = new long[U];
		for(long s = 1; s < U; s++)
		{
			dp[s] = sum[s];
			for(long t = s; t > 0; t = (t - 1) & s)
			{
				if(t == s)
					continue;

				chmax(ref dp[s], dp[s ^ t] + sum[t]);
			}
		}
		WriteLine(dp[U - 1]);
	}
}

public static class BinaryRepresentation
{
	/*
	* initialize: array = { 0, 1, 2, ..., N - 1 } 
	* do { ... } while(nextPermutarion(ref array));
	*/
	public static bool nextPermutation(ref int[] array)
	{
		int len = array.Length;
		int i = len - 2;
		while((i >= 0) && (array[i] > array[i + 1]))
			i--;
		if(i < 0)
			return false;

		int pivot = array[i];
		int j = i + 1;
		while((j < len - 1) && (array[j + 1] > pivot))
			j++;
		
		int tmp = array[i];
		array[i] = array[j];
		array[j] = tmp;
		
		Array.Reverse(array, i + 1, len - i - 1);

		return true;
	}

	/* 
	* nCk
	* initialize: comb = (1 << k) - 1
	* while(comb < (1 << n)) { ...; comb = nextCombination(comb); };
	*/
	public static int nextCombination(int comb)
	{
		int x = comb & -comb;
		int y = comb + x;
		return (((comb & ~y) /x) >> 1) | y;
	}

	public static int popcnt(int v) {
		v = v - ((v >> 1) & 0x55555555);
		v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
		return ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24;
	}

	public static long popcnt(long v) {
		v = v - ((v >> 1) & 0x5555555555555555);
		v = (v & 0x3333333333333333) + ((v >> 2) & 0x3333333333333333);
		return ((v + (v >> 4) & 0xF0F0F0F0F0F0F0F) * 0x101010101010101) >> 56;
	}
}

public static class MyIO
{
	private static string[] args = new string[0];
	private static int cnt = 0;
	private static IEnumerable<string> getArgs(long N) => Range(0, N).Select(_ => getArg());
	private static string getArg()
	{
		if(cnt == args.Length) { args = Console.ReadLine().Split(); cnt = 0; }
		return args[cnt++];
	}

	public static int GetInt() => int.Parse(getArg());
	public static long GetLong() => long.Parse(getArg());
	public static double GetDouble() => double.Parse(getArg());
	public static decimal GetDecimal() => decimal.Parse(getArg());
	public static string GetString() => getArg();
	public static char GetChar() => getArg()[0];
	public static int[] GetInts(long N) => getArgs(N).Select(int.Parse).ToArray();
	public static long[] GetLongs(long N) => getArgs(N).Select(long.Parse).ToArray();
	public static double[] GetDoubles(long N) => getArgs(N).Select(double.Parse).ToArray();
	public static decimal[] GetDecimals(long N) => getArgs(N).Select(decimal.Parse).ToArray();
	public static string[] GetStrings(long N) => getArgs(N).ToArray();
}

public static class MyUtil
{
	public static void chmax<T>(ref T x, T y) where T : IComparable<T> { if(x.CompareTo(y) < 0) x = y; }
	public static void chmin<T>(ref T x, T y) where T : IComparable<T> { if(x.CompareTo(y) > 0)	x = y; }
	public static void swap<T>(ref T x, ref T y) { T tmp = x; x = y; y = tmp; }
	public static long rightShift(long x, long y) => (x >> (int)y);
	public static long leftShift(long x, long y) => (x << (int)y);
	public static bool contains(long s, long x) => (rightShift(s, x) & 1L) == 1L;
	public static long gcd(long x, long y) => (y == 0) ? x : gcd(y, x % y);
	public static long lcm(long x, long y) => (x / gcd(x,y)) * y;	
	public static IEnumerable<int> Range(long start, long count) => Enumerable.Range((int)start, (int)count);
	public static void Sort(this List<string> source) => source.Sort(StringComparer.Ordinal);
}


Measured memory_bytes: 28524