#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];
int dp [1 << MAX_N];
const int INF = 1e9;

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

	fill(dp,dp + (1 << N),-INF);
	dp [0] = 0;
	FOR(mask,0,1 << N){
		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 [i] [j]);
			}
			break;
		}
	}

	printf("%d\n",dp [(1 << N) - 1]);

	return 0;
}