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

#define FOR(i,l,r) for(int i = (int) (l);i < (int) (r);i++)
template<typename T> bool chmax(T& a,const T& b){ return a < b ? (a = b,true) : false; }
template<typename T> bool chmin(T& a,const T& b){ return b < a ? (a = b,true) : false; }
typedef long long ll;

int N;
const int MAX_N = 24;
int edge [MAX_N] [MAX_N];
const int INF = 1e9;
const int MAGIC = 1000;

int bit_count(int x)
{
	int res = 0;
	for(;x;x -= x & -x) res++;
	return res;
}

int solve(vector<int>& v)
{
	int n = v.size();
	vector<int> dp(1 << n,-INF);
	dp [0] = 0;
	FOR(mask,0,1 << n) if(dp [mask] >= 0){
		FOR(i,0,n) if((mask >> i & 1) == 0){
			FOR(j,i + 1,n) if((mask >> j & 1) == 0){
				int nmask = mask | (1 << i) | (1 << j);
				chmax(dp [nmask],dp [mask] + edge [v [i]] [v [j]]);
			}
			break;
		}
	}
	return dp [(1 << n) - 1];
}

int main()
{
	scanf("%d",&N);
	FOR(i,0,N) FOR(j,0,N){
		scanf("%d",&edge [i] [j]);
	}

	int ans = 0,cnt = 0;
	FOR(mask,0,1 << N) if(bit_count(mask) == N / 2 / 2 * 2){
		vector<int> v,w;
		FOR(i,0,N){
			if(mask >> i & 1){
				v.push_back(i);
			}
			else{
				w.push_back(i);
			}
		}
		chmax(ans,solve(v) + solve(w));
		if(++cnt == MAGIC) break;
	}

	printf("%d\n",ans);

	return 0;
}