#include<cstdio>
#include<cstring>
#include<algorithm>
#include<iostream>
#include<cmath>
using namespace std;
int head[12000];
int next[50000];
int to[50000];
int val[50000];
int d[12000];
int q[12000];
int n,m;
int tot=1;
int ans=0;
int S,T;
int s[200][200];
void add(int x,int y,int v)
{tot++;next[tot]=head[x];head[x]=tot;to[tot]=y;val[tot]=v;tot++;next[tot]=head[y];head[y]=tot;to[tot]=x;val[tot]=0;
}
bool bfs(int S,int T)
{int r=0;int l=0;memset(q,0,sizeof(q));memset(d,-1,sizeof(d));q[r++]=S;d[S]=0;while(l<r){  int now=q[l];for(int i=head[now];i;i=next[i]){if(d[to[i]]==-1&&val[i]!=0){d[to[i]]=d[now]+1;q[r++]=to[i];}}l++;}return d[T]!=-1;
}
int dfs(int x,int flow)
{if(x==T){return flow;}int now_flow;int used=0;for(int i=head[x];i;i=next[i]){if(d[to[i]]==d[x]+1&&val[i]!=0){now_flow=dfs(to[i],min(flow-used,val[i]));val[i]-=now_flow;val[i^1]+=now_flow;used+=now_flow;if(now_flow==flow){return flow;}}}if(used==0){d[x]=-1;}return used;
}
void dinic()
{while(bfs(S,T)==true){ans-=dfs(S,0x3f3f3f);}
}
int main()
{scanf("%d%d",&m,&n);S=n*m+1;T=n*m+2;for(int i=1;i<=m;i++){for(int j=1;j<=n;j++){scanf("%d",&s[i][j]);ans+=s[i][j];if((i+j)%2==0){add(S,n*(i-1)+j,s[i][j]);}else{add(n*(i-1)+j,T,s[i][j]);}}}for(int i=1;i<=m;i++){for(int j=1;j<=n;j++){if((i+j)%2==0){if(i-1>0){add(n*(i-1)+j,n*(i-2)+j,1<<30);}if(j-1>0){add(n*(i-1)+j,n*(i-1)+j-1,1<<30);}if(i+1<=m){add(n*(i-1)+j,n*i+j,1<<30);}if(j+1<=n){add(n*(i-1)+j,n*(i-1)+j+1,1<<30);}}}}dinic();printf("%d",ans);
}