//sursa de 40 de puncte

#include<fstream>
#include<vector>
#define NMAX 8200
#define vec G[nod][i]
using namespace std;
vector<short> G[NMAX];
short n,l[NMAX],r[NMAX],c;
bool use[NMAX],useL[NMAX],useR[NMAX];
void read()
{
	ifstream fin("felinare.in");
	short m,x,y;
	fin>>n>>m;
	while(m--)
	{
		fin>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
	fin.close();
}
void print()
{
	ofstream fout("felinare.out");
	fout<<2*n-c<<'\n';
	fout.close();
}
bool pairup(int nod)
{
	if(use[nod])
		return 0;
	use[nod]=1;
	for(size_t i=0;i<G[nod].size();i++)
		if(!r[vec])
		{
			r[vec]=nod;
			l[nod]=vec;
			useL[nod]=1;
			return 1;
		}
	for(size_t i=0;i<G[nod].size();i++)
		if(pairup(r[vec]))
		{
			r[vec]=nod;
			l[nod]=vec;
			useL[nod]=1;
			return 1;
		}
	return 0;
}
int main()
{
	read();
	for(short sw=1;sw;)
	{
		sw=0;
		for(int i=1;i<=n;i++)
			if(!r[i])
				if(pairup(i))
					c+=sw=1;
	}
	print();
	return 0;
}