#line 1 "a.cpp"
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#line 3 "/home/kotatsugame/library/graph/bimatch.cpp"
struct bimatch{
	int n;
	vector<vector<int> >G;
	vector<int>match;
	vector<bool>used;
	bimatch(int _n=0):n(_n),G(n),match(n),used(n){}
	void add_edge(int u,int v)
	{
		G[u].push_back(v);
		G[v].push_back(u);
	}
	bool dfs(int v)
	{
		used[v]=true;
		for(int u:G[v])
		
		{
			int w=match[u];
			if(w<0||!used[w]&&dfs(w))
			{
				match[v]=u;
				match[u]=v;
				return true;
			}
		}
		return false;
	}
	int count()
	{
		int ans=0;
		bool flag=true;
		fill(match.begin(),match.end(),-1);
		while(flag)
		{
			flag=false;
			fill(used.begin(),used.end(),false);
			for(int v=0;v<n;v++)if(match[v]<0&&dfs(v))ans++,flag=true;
		}
		return ans;
	}
};
#line 6 "a.cpp"
int N,M;
main()
{
	cin>>N>>M;
	vector<pair<int,pair<int,int> > >A(N*M);
	for(int i=0;i<N;i++)for(int j=0;j<M;j++)
	{
		cin>>A[i*M+j].first;
		A[i*M+j].second=make_pair(i,j);
	}
	sort(A.begin(),A.end());
	int ans=0;
	for(int i=0;i<A.size();)
	{
		if(A[i].first==0)
		{
			i++;
			continue;
		}
		int j=i;
		bimatch P(N+M);
		while(j<A.size()&&A[i].first==A[j].first)
		{
			P.add_edge(A[j].second.first,A[j].second.second+N);
			j++;
		}
		i=j;
		ans+=P.count();
	}
	cout<<ans<<endl;
}