#include<cstdio>

#include<cstdlib>

#include<cstring>

#include<cmath>

#include<vector>

#include<algorithm>

using namespace  std;

const int N=301,M=301;

const int INF=0x3fffffff;

int sum[N][M],arr[M];

int find_max(int a[N][M],int n,int m)

{

 if(n==0||m==0)return 0;

 int i,j,up,down, ret=-INF;

 memset(sum,0,sizeof(sum));

 for(i=1;i<=n;i++)

 	for(j=1;j<=m;j++)

	 	sum[i][j]=sum[i-1][j]+a[i][j];

 arr[0]=0;

 for(up=1;up<=n;up++)

 	for(down=up;down<=n;down++)

	 	{

	 	 for(i=1;i<=m;i++)

	 	 	arr[i]=arr[i-1]+(sum[down][i]-sum[up-1][i]);

	 	 int mini=0;

	 	 for(i=1;i<=m;i++)

	 	 	{

	 	 	 ret=max(ret,arr[i]-mini);

	 	 	 mini=min(mini,arr[i]);

			}

	 	}

 return max(0,ret);

}

int main()

{freopen("t.txt","r",stdin);

 int n;

 while(scanf("%d",&n)!=EOF)

 	{

 	 int num[N][M];

 	 for(int i=1;i<=n;i++)

 	 	for(int j=1;j<=n;j++)

 	 		scanf("%d",&num[i][j]);

 	 printf("%d\n",find_max(num,n,n));

	}

 return 0;

}