#include <cstdio>

#include <cstring>

#include <iostream>

#include <algorithm>

using namespace std;

#define F(i,j,k) for (int i=j;i<=k;++i)

int dp[2][1<<21],n,a[20][20];

void print(int x)

{F(i,0,n)printf("%d",(x>>i)&1);}

int main()

{

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

    {

        if (!n){printf("0\n");continue;}

        F(i,0,n-1) F(j,0,n-1) scanf("%d",&a[i][j]);

        int now=1,pre=0;

        memset(dp[now],0,sizeof dp[now]);

        F(i,0,n-1)

            F(j,0,n-1)

            {

                now^=1;pre^=1;

                memset(dp[now],0,sizeof dp[now]);

                F(s,0,(1<<(n+1))-1)

                {

//                    print(s); printf(" is %d to",dp[pre][s]);

                    if ((!(s&(1<<j)))&&(!(s&(1<<(j+1))))) dp[now][s|(1<<j)|(1<<(j+1))]=max(dp[now][s|(1<<(j+1))|(1<<j)],dp[pre][s]+a[i][j]);

                    dp[now][s&(~(1<<j))&(~(1<<(j+1)))]=max(dp[now][s&(~(1<<j))&(~(1<<(j+1)))],dp[pre][s]);

//                    printf("\n");

                }

                if (j==n-1)

                {

                    now^=1;pre^=1;

                    memset(dp[now],0,sizeof dp[now]);

                    F(s,0,(1<<(n+1))-1)

                    {

//                        print(s); printf(" --> "); print(((s<<1)&((1<<(n+1))-1))); printf("\n");

                        dp[now][((s<<1)&((1<<(n+1))-1))]=max(dp[pre][s],dp[now][((s<<1)&((1<<(n+1))-1))]);

                    }

                }

//                printf("\n");

            }

        int ans=0;

        F(s,0,(1<<(n+1))-1) ans=max(ans,dp[now][s]);

        printf("%d\n",ans);

    }

}