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

int n, a[25][25], dp[1 << 24], tong[25], cnt;

signed main()
{
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	cin >> n;
	for (int i = 0; i < n; i ++ )
		for (int j = 0; j < n; j ++ )
			cin >> a[i][j];
	for (int i = 3; i < (1 << n); i ++ )
	{
		if (__builtin_popcount(i) & 1) continue;
		int cnt = 0;
		for (int j = 0; j < n; j ++ )
			if (i >> j & 1) tong[ ++ cnt] = j;
		for (int j = 2; j <= cnt; j ++ )
			dp[i] = max(dp[i - (1 << tong[1]) - (1 << tong[j])] + a[tong[1]][tong[j]], dp[i]);
	}
	cout << dp[(1 << n) - 1];
	return 0;
}