#include <iostream>
#include<fstream>
using namespace std;
/*ifstream f("date.in");
ofstream g("date.out");*/
int n,s=0,i,j,a[51][51],k,p;
int maxx=-20000000;
int maxim(int a,int b)
{
	if(a<b)return b;
	else return a;
}
int main() {
	cin>>n;
	//f>>n;
	for(i=1;i<=n;i++)
		for(j=1;j<=n;j++)
		{	cin>>a[i][j];
			//f>>a[i][j];
			//a[i][j]=a[i-1][j]+a[i][j-1]-a[i-1][j-1]+a[i][j];
		}
		for(i=1;i<=n;i++)
			for(j=1;j<=n;j++)
				for(k=i+1;k<=n;k++)
					for(p=j+1;p<=n;p++)
						if(p-j==k-i)
						{
							s=0;
							for(int i1=1;i1<=p-j-1;i1++)
								s+=a[i][j+i1]+a[i+i1][j]+a[i+i1][p]+a[k][j+i1];
							s+=a[i][j]+a[k][p]+a[k][j]+a[i][p];
							maxx=maxim(maxx,s);	
						}
							
			cout<<maxx;
	
	return 0;
}