#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int read()
{int x=0,f=1; char ch=getchar();while (ch<'0' || ch>'9') {if (ch=='-') f=-1; ch=getchar();}while (ch>='0' && ch<='9') {x=x*10+ch-'0'; ch=getchar();}return x*f;
}
#define maxm 1000010
#define maxn 10010
int n,m,tot;
struct EdgeNode{int next,to,cap;}edge[maxm];
int head[maxn],cnt=1;
void add(int u,int v,int w)
{cnt++;edge[cnt].next=head[u]; head[u]=cnt; edge[cnt].cap=w; edge[cnt].to=v;
}
void insert(int u,int v,int w) {add(u,v,w); add(v,u,0);}int val[110][110];int dis[maxn],que[maxn<<1],cur[maxn],S,T;
bool bfs()
{for (int i=S; i<=T; i++) dis[i]=-1;que[0]=S; dis[S]=0; int he=0,ta=1;while (he<ta){int now=que[he++];for (int i=head[now]; i; i=edge[i].next)if (edge[i].cap && dis[edge[i].to]==-1)dis[edge[i].to]=dis[now]+1,que[ta++]=edge[i].to;}return dis[T]!=-1;
}
int dfs(int loc,int low)
{if (loc==T) return low;int w,used=0;for (int i=cur[loc]; i; i=edge[i].next)if (edge[i].cap && dis[edge[i].to]==dis[loc]+1){w=dfs(edge[i].to,min(low-used,edge[i].cap));edge[i].cap-=w; edge[i^1].cap+=w;used+=w; if (edge[i].cap) cur[loc]=i;if (used==low) return low;}if (!used) dis[loc]=-1;return used;
}
#define inf 0x7fffffff
int dinic()
{int tmp=0;while (bfs()){for (int i=S; i<=T; i++) cur[i]=head[i];tmp+=dfs(S,inf);}return tmp;
}
int locate(int x,int y) {return (x-1)*m+y;}
int main()
{n=read(),m=read();for (int i=1; i<=n; i++)for (int j=1; j<=m; j++)val[i][j]=read(),tot+=val[i][j];S=0,T=n*m+1;for (int i=1; i<=n; i++)for (int j=1; j<=m; j++)if ((i+j)%2==1){insert(S,locate(i,j),val[i][j]);if (i+1<=n) insert(locate(i,j),locate(i+1,j),inf);if (i-1>=1) insert(locate(i,j),locate(i-1,j),inf);if (j+1<=m) insert(locate(i,j),locate(i,j+1),inf);if (j-1>=1) insert(locate(i,j),locate(i,j-1),inf);}else insert(locate(i,j),T,val[i][j]);int maxflow=dinic();printf("%d\n",tot-maxflow);return 0;
}