#include <cstdio>

 #include <cstring>

 #include <queue>

 #include <vector>

 #define maxn 410

 #define oo 0x3f3f3f3f

 using namespace std;

 struct Edge {

     int u, v, f;

     Edge( int u, int v, int f ):u(u),v(v),f(f){}

 };

 struct Dinic {

     int n, src, dst;

     vector<Edge> edge;

     vector<int> g[maxn];

     int dep[maxn], cur[maxn];

     void init( int n, int src, int dst ) {

         this->n = n;

         this->src = src;

         this->dst = dst;

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

             g[u].clear();

         edge.clear();

     }

     void add_edge( int u, int v, int f ) {

         g[u].push_back( edge.size() );

         edge.push_back( Edge(u,v,f) );

         g[v].push_back( edge.size() );

         edge.push_back( Edge(v,u,) );

     }

     bool bfs() {

         queue<int> qu;

         memset( dep, , sizeof(dep) );

         qu.push( src );

         dep[src] = ;

         while( !qu.empty() ) {

             int u=qu.front();

             qu.pop();

             for( int t=; t<g[u].size(); t++ ) {

                 Edge &e = edge[g[u][t]];

                 if( e.f && !dep[e.v] ) {

                     dep[e.v] = dep[e.u]+;

                     qu.push( e.v );

                 }

             }

         }

         return dep[dst];

     }

     int dfs( int u, int a ) {

         if( u==dst || a== ) return a;

         int remain=a, past=, na;

         for( int &t=cur[u]; t<g[u].size(); t++ ) {

             Edge &e = edge[g[u][t]];

             Edge &ve = edge[g[u][t]^];

             if( dep[e.v]==dep[e.u]+ && e.f && (na=dfs(e.v,min(remain,e.f))) ) {

                 remain -= na;

                 past += na;

                 e.f -= na;

                 ve.f += na;

                 if( !remain ) break;

             }

         }

         return past;

     }

     int maxflow() {

         int flow = ;

         while( bfs() ) {

             memset( cur, , sizeof(cur) );

             flow += dfs(src,oo);

         }

         return flow;

     }

 };

 int n, m;

 int idx[][], id_clock;

 int arr[][], sum;

 int di[] = { , , +, - };

 int dj[] = { +, -, ,  };

 Dinic D;

 int main() {

     while( scanf( "%d", &n )== ) {

         id_clock = ;

         sum = ;

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

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

                 scanf( "%d", &arr[i][j] );

                 sum += arr[i][j];

                 idx[i][j] = ++id_clock;

             }

         D.init( id_clock+, id_clock+, id_clock+ );

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

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

                 if( (i+j)& ) {

                     D.add_edge( D.src, idx[i][j], arr[i][j] );

                     for( int d=; d<; d++ ) {

                         int ni = i+di[d];

                         int nj = j+dj[d];

                         if( <=ni&&ni<=n && <=nj&&nj<=n ) {

                             int u = idx[i][j];

                             int v = idx[ni][nj];

                             D.add_edge( u, v, oo );

                         }

                     }

                 } else {

                     D.add_edge( idx[i][j], D.dst, arr[i][j] );

                 }

             }

         printf( "%d\n", sum-D.maxflow() );

     }

 }