#include <cstdio>

#include <cstring>

#include <queue>

#include <set>

#include <map>

#include <stack>

#include <cstdlib>

#include <algorithm>

#include <vector>

#include <cmath>

using namespace std;

typedef long long LL;

typedef pair<int,int>pii;

const int N=1e2+;

const int INF=0x3f3f3f3f;

int n;

LL dp[N][N][N*];

LL a[N][N];

int dx[]= {,-};

int dy[]= {-,};

int main()

{

    while(~scanf("%d",&n))

    {

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

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

                scanf("%I64d",&a[i][j]);

        dp[][][]=a[][];

        for(int k=; k<=*n-; ++k)

        {

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

            {

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

                {

                    int x1=i,y1=k-i+,x2=j,y2=k-j+;

                    if(y1<||y1>n||y2<||y2>n)continue;

                    LL tmp=a[x1][y1]+a[x2][y2];

                    if(x1==x2&&y1==y2)tmp-=a[x1][y1];

                    bool flag=;

                    for(int k1=; k1<; ++k1)

                    {

                        for(int k2=; k2<; ++k2)

                        {

                            if(x1+dx[k1]<||y1+dy[k1]<)continue;

                            if(x2+dx[k2]<||y2+dy[k2]<)continue;

                            int k3=x1+dx[k1],k4=x2+dx[k2];

                            if(flag)dp[i][j][k]=dp[k3][k4][k-]+tmp,flag=;

                            else dp[i][j][k]=max(dp[i][j][k],dp[k3][k4][k-]+tmp);

                        }

                    }

                }

            }

        }

        printf("%I64d\n",dp[n][n][*n-]);

    }

    return ;

}