#include <iostream>
#include <algorithm>

using namespace std;

int v[55][55];

int square(int n,int beg,int lenght,int line){
    int s=0;
    for(int i=beg;i<=beg+lenght;++i){
        s+=v[line][i];
    }
    for(int i=line+1;i<=line+lenght;++i){
        s+=v[i][beg+lenght];
    }
    for(int i=beg+lenght-1;i>=beg;--i){
        s+=v[line+lenght][i];
    }
    for(int i=line+lenght-1;i>line;--i){
        s+=v[i][beg];
    }
    return s;
}
int main(){

    int n;
    int maxim=-20000000,maxim2=-2000;
    cin >>n;
    for(int i=1;i<=n;++i){
        for(int j=1;j<=n;++j){
            cin >>v[i][j];
        }
    }
    for(int i=1;i<=n;++i){
        for(int j=1;j<=n;++j){
            for(int l=1;l+j-1<=n;++l){
                if(maxim<square(n, j, l, i))
                    maxim=square(n, j, l, i);
            }
            if(maxim2<v[i][j]){
                maxim2=v[i][j];
            }
        }
    }
    cout <<max(maxim,maxim2);
    return 0;
}