#include <bits/stdc++.h>

using namespace std;

int board[25][25];
int dp[1 << 24];

int main(void)
{
	cin.tie(0);
	ios::sync_with_stdio(false);

	int n;

	cin >> n;

	for (int i = 0; i < n; i++)
	{
		for (int j = 0; j < n; j++)
		{
			cin >> board[i][j];
		}
	}
	memset(dp, -1, sizeof(dp));
	dp[0] = 0;

	for (int i = 0; i < (1 << n); i++)
	{
		if (__builtin_popcount(i) % 2 == 1) continue;
		for (int j = 0; j < n; j++)
		{
			if ((i & (1 << j)) == 0)
			{
				for (int k = j + 1; k < n; k++)
				{
					if ((i & (1 << k)) == 0)
					{
						int mask = i + (1 << j) + (1 << k);
						dp[mask] = max(dp[mask], dp[i] + board[j][k]);
					}
				}
			}
		}
	}

	cout << dp[(1 << n) - 1] << '\n';

	return 0;
}