#include<bits/stdc++.h>
using namespace std;
int a[210][210], s[210][210], f[210];
int main()
{
    int n;scanf("%d", &n);
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)
    {  
        scanf("%d", &a[i][j]);
        s[i][j] = s[i][j-1] + a[i][j];
    }
    int ans = -0xffffffff;
    for(int x=1;x<=n;x++)
        for(int y=x;y<=n;y++)
        {
            f[0] = 0;
            for(int i=1;i<=n;i++)
            {
                if(f[i-1] > 0)f[i] = (s[i][y] - s[i][x-1]) + f[i-1];
                else        f[i] = (s[i][y] - s[i][x-1]);
            
                ans = max(ans, f[i]);
            }
        }
    printf("%d\n", ans);
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
int a[210][210],s[210][210],f[210];
int main()
{
    int n;scanf("%d",&n);
    for(int i=1;i<=n;i++)for(int j=1;j<=n;j++)
    {  
        scanf("%d",&a[i][j]);
        s[i][j]=s[i][j-1]+a[i][j];
    }
    int ans=-0xffffffff;
    for(int x=1;x<=n;x++)
        for(int y=x;y<=n;y++)
        {
            f[0]=0;
            for(int i=1;i<=n;i++)
            {
                if(f[i-1]>0)f[i]= (s[i][y] -s[i][x-1] ) + f[i-1];
                else        f[i]= (s[i][y] -s[i][x-1] );
            
                ans=max(ans,f[i]);
            }
        }
    printf("%d\n",ans);
    return 0;
}