#include<iostream>
using namespace std;

int a[55][55],s1[55][55][55],s2[55][55][55],i,j,n,k,l,mx;

int main()
{
	cin >> n;
	mx=-(1 << 30);
	for (i=1;i<=n;i++)
		for (j=1;j<=n;j++)
		{
			cin >> a[i][j];
			if (a[i][j]>mx)
				mx=a[i][j];
		}
	for (i=1;i<=n;i++)
		for (j=i;j<=n;j++)
			for (k=1;k<=n;k++)
				s1[i][j][k]=s1[i][j-1][k]+a[j][k];
	for (i=1;i<=n;i++)
		for (j=i;j<=n;j++)
			for (k=1;k<=n;k++)
				s2[i][j][k]=s2[i][j-1][k]+a[k][j];
	for (i=1;i<=n;i++)
		for (j=1;j<=n;j++)
			for (k=i+1;k<=n;k++)
				for (l=j+1;l<=n;l++)
					mx=max(mx,s1[i][k][j]+s1[i][k][l]+s2[j][l][i]+s2[j][l][k]-a[i][j]-a[i][l]-a[k][l]-a[k][j]);
	cout << mx;
	return 0;
}