#include <bits/stdc++.h>
using namespace std;
int hang[50],lie[50],mp[50][50],ans,n;
void dfs(int x,int y,int now,int num){
	if (num==n) {
		ans=max(now,ans);
		return; 
	}
	while (x<=n&&y<=n){
		y++;
		if (y>n) {
			x++;y=1;
		} 
		if (hang[x]!=0||lie[y]!=0||x==y) continue;
		hang[x]=1;
		lie[x]=1;
		hang[y]=1;
		lie[y]=1;
		dfs(x,y,now+mp[x][y],num+2);
		hang[x]=0;
		lie[x]=0;
		hang[y]=0;
		lie[y]=0;
	}
}
signed main ()
{
	cin>>n;
	for (int i=1;i<=n;i++)
		for (int j=1;j<=n;j++)
			cin>>mp[i][j];
	hang[0]=1;
	lie[0]=1;
	dfs(0,0,0,0);
	cout<<ans;
	return 0;
}