#include <iostream>
using namespace std;

int n,cost[24][24],ma = 0;
int use = 0;

void dfs(int now,int sum){
	if(now == n / 2){
		ma = max(ma,sum);
		return;
	}
	int mi = 50;
	for(int i = 0;i < n;i++){
		if(!(use >> i & 1)) mi = min(mi,i);
	}
	use |= 1 << mi;
	for(int i = mi + 1;i < n;i++){
		use |= 1 << i;
		dfs(now + 1,sum + cost[mi][i]);
		use &= ~(1 << i);
	}
	use &= ~(1 << mi);
}

int main(){
	cin >> n;
	for(int i = 0;i < n;i++){
		for(int j = 0;j < n;j++){
			cin >> cost[i][j];
		}
	}
	dfs(0,0);
	cout << ma << endl;
	return 0;
}