#include <cstdio>

using namespace std;

int v[105][105];

int main(){
    int n,rasp=-105,sum;
    
    scanf("%d",&n);
    
    for(register int i=1;i<=n;++i){
        for(register int j=1;j<=n;++j){
            scanf("%d",&v[i][j]);
            if(v[i][j]>rasp){
                rasp=v[i][j];
            }
        }
    }
    
    for(register int k=2;k<=n;++k){
        for(register int i=1;i<=n;++i){
            for(register int j=1;j<=n;++j){
                int x,y;
                sum=0;
                for(x=j;x<=j+k-1;++x){
                    sum=sum+v[i][x]+v[i+k-1][x];
                }
                for(y=i+1;y<=i+k-2;++y){
                    sum=sum+v[y][j]+v[y][j+k-1];
                }
                if(sum>rasp){
                    rasp=sum;
                }
            }
        }
    }
    
    printf("%d\n",rasp);
    
    return 0;
}