#include<fstream>
#include<iostream>
using namespace std;
//ifstream in("joctv.in");
//ofstream out("joctv.out");

int n, m[102][102], sc[102][102], rasp = -100000000, val, sact, sl[52][52];

int main(){
	int player_unu=0;

	cin>>n;

	for(int i = 1;i<=n; i++)
		for(int j = 1;j<=n; j++)
		{
			cin>>m[i][j];
			sc[i][j] = sc[i-1][j] + m[i][j];  
			sl[i][j] = sl[i][j-1] + m[i][j];
			if(m[i][j]>rasp)
				rasp = m[i][j];
		}

	for(int i = 1;i<=n; i++)
		for(int j = 1;j<=n; j++)
		{
			for(int h = 0;h<n-j+1 && h<n-i+1; h++)
			{
				if(sc[i+h][j] - sc[i-1][j] + sc[i+h][j+h] - sc[i-1][j+h] + sl[i][j+h-1] - sl[i][j] + sl[i+h][j+h-1] - sl[i+h][j]>rasp)
					rasp = sc[i+h][j] - sc[i-1][j] + sc[i+h][j+h] - sc[i-1][j+h] + sl[i][j+h-1] - sl[i][j] + sl[i+h][j+h-1] - sl[i+h][j];
			}
		}

		cout<<rasp;
	return player_unu;
}