#include<stdio.h>
#include<cctype>
#include<vector>
#include<algorithm>
#include<cstring>
#include<queue>
using namespace std;
#define INF 0x3f3f3f3f
int n,m,level[30003],iter[30003],a[103][103];
struct edges{int to,cap,rev;
};
vector<edges>G[200003];
queue<int>q;
inline int readint(){int p=0;char c=getchar();for(;!isdigit(c);c=getchar());for(;isdigit(c);c=getchar())p=p*10+c-'0';return p;
}
inline void addedge(int from,int to,int cap){G[from].push_back((edges){to,cap,G[to].size()});G[to].push_back((edges){from,0,G[from].size()-1});
}
void bfs(int s){memset(level,-1,sizeof(level));level[s]=0;q.push(s);while(!q.empty()){int u=q.front();q.pop();for(int i=0;i<G[u].size();++i){edges& e=G[u][i];if(level[e.to]<0&&e.cap>0){level[e.to]=level[u]+1;q.push(e.to);}}}
}
int dfs(int u,int t,int f){if(u==t)return f;for(int& i=iter[u];i<G[u].size();++i){edges& e=G[u][i];if(e.cap>0&&level[e.to]>level[u]){int d=dfs(e.to,t,min(f,e.cap));if(d){e.cap-=d;G[e.to][e.rev].cap+=d;return d;}}}return 0;
}
int max_flow(int s,int t){int flow=0;while(1){bfs(s);if(level[t]<0)return flow;memset(iter,0,sizeof(iter));int f;while(f=dfs(s,t,INF))flow+=f;}
}
int main(){memset(a,-1,sizeof a);n=readint(),m=readint();for(int i=1;i<=n;++i)for(int j=1;j<=m;++j)a[i][j]=readint();for(int i=1;i<=n;++i)for(int j=1;j<=m;++j){if(a[i][j]==1)addedge(0,(i-1)*m+j,INF);elseif(a[i][j]==2)addedge((i-1)*m+j,n*m+1,INF);if(a[i][j]==2)continue;if(a[i+1][j]==2||a[i+1][j]==0)addedge((i-1)*m+j,i*m+j,1);if(a[i-1][j]==2||a[i-1][j]==0)addedge((i-1)*m+j,(i-2)*m+j,1);if(a[i][j+1]==2||a[i][j+1]==0)addedge((i-1)*m+j,(i-1)*m+j+1,1);if(a[i][j-1]==2||a[i][j-1]==0)addedge((i-1)*m+j,(i-1)*m+j-1,1);}printf("%d\n",max_flow(0,n*m+1));return 0;
}