#include<bits/stdc++.h>
using namespace std;const int MAXN=700005+1;
const int MAXM=700000;
const int INF=0x3f3f3f3f;
struct Edge{int to,next,cap,flow,cost;
}edge[MAXM];
int head[MAXN],tol;
int pre[MAXN],dis[MAXN];
bool vis[MAXN];int n;
void init(){tol=0;memset(head,-1,sizeof(head));
}void addedge(int u,int v,int cap,int cost){edge[tol].to=v;edge[tol].cap=cap;edge[tol].cost=cost;edge[tol].flow=0;edge[tol].next=head[u];head[u]=tol++;edge[tol].to=u;edge[tol].cap=0;edge[tol].cost=-cost;edge[tol].flow=0;edge[tol].next=head[v];head[v]=tol++;
}bool spfa(int s,int t){queue<int> q;memset(dis,INF,sizeof(dis));memset(vis,false,sizeof(vis));memset(pre,-1,sizeof(pre));dis[s]=0;vis[s]=true;q.push(s);while(!q.empty()){int u=q.front();q.pop();vis[u]=false;for(int i=head[u];i!=-1;i=edge[i].next){int v=edge[i].to;if(edge[i].cap>edge[i].flow&&dis[v]>dis[u]+edge[i].cost){dis[v]=dis[u]+edge[i].cost;pre[v]=i;if(!vis[v]){vis[v]=true;q.push(v);}}}}if(pre[t]==-1)return false;elsereturn true;
}int minCostMaxFlow(int s,int t,int &cost){int flow=0;cost=0;while(spfa(s,t)){int Min=INF;for(int i=pre[t];i!=-1;i=pre[edge[i^1].to]){if(Min>edge[i].cap-edge[i].flow)Min=edge[i].cap-edge[i].flow;}for(int i=pre[t];i!=-1;i=pre[edge[i^1].to]){edge[i].flow+=Min;edge[i^1].flow-=Min;cost+=edge[i].cost*Min;}flow+=Min;}return flow;
}void show(int s){bool vis[20];queue<int> q;vis[s]=1;q.push(s);while(!q.empty()){int u=q.front();q.pop();cout<<"u="<<u<<endl;for(int i=head[u];i!=-1;i=edge[i].next){int v=edge[i].to;if(vis[v]==0){vis[v]=1;q.push(v);}}}cout<<endl;
}/* EK end */int a[55][55];int k;inline int getid(int i,int j,int isout){return (i-1)*n+j+isout*(n*n);
}int main(){init();scanf("%d%d",&n,&k);int si=2*n*n+1,so=2*n*n+2;addedge(si,so,k,0);//最多走k次int t=2*n*n+3;for(int i=1;i<=n;i++){for(int j=1;j<=n;j++){int c;scanf("%d",&c);addedge(getid(i,j,0),getid(i,j,1),1,-c);//拿走它，获得价值，费用是相反数addedge(getid(i,j,0),getid(i,j,1),INF,0);//不拿就不拿呗
        }}for(int i=1;i<=n;i++){for(int j=1;j<=n;j++){if(i+1<=n)addedge(getid(i,j,1),getid(i+1,j,0),INF,0);if(j+1<=n)addedge(getid(i,j,1),getid(i,j+1,0),INF,0);}}addedge(so,getid(1,1,0),INF,0);addedge(getid(n,n,1),t,INF,0);//show(si);int cost=0;int flow=minCostMaxFlow(si,t,cost);printf("%d\n",-cost);}