#include <stdio.h>
#define FOR(i,l,r) for(int (i) = (l);(i) < (r);(i)++)
#define MAX_N 24

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

int main(void)
{
	scanf("%d",&N);
	FOR(i,0,N) FOR(j,0,N){
		scanf("%d",&edge [i] [j]);
	}
	FOR(mask,0,1 << N) dp [mask] = -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);
				if(dp [mask] + edge [i] [j] > dp [nmask]){
					dp [nmask] = dp [mask] + edge [i] [j];
				}
			}
			break;
		}
	}
	printf("%d\n",dp [(1 << N) - 1]);

	return 0;
}