using namespace std;

#define NMAX 100005
#include<vector>
#include<fstream>

ifstream fin("dfs.in");
ofstream fout("dfs.out");

vector <int> G[NMAX];
int N,M,use[NMAX];

void Read()
{
	fin>>N>>M;
	for(int i=1;i<=M;i++)
	{
		int x,y;
		fin>>x>>y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void DFS(int nod)
{
	use[nod]=1;
	vector<int>::iterator it;
	for(it=G[nod].begin();it!=G[nod].end();it++)
		if(!use[*it])
			DFS(*it);
	
}

int main()
{
	int nr=0,i;
	Read();
	for(i=1;i<=N;i++)
		if(!use[i])
		{
			DFS(i);
			nr++;
		}
	fout<<nr;
	return 0;
}