using namespace std;

#include<fstream>
#include<vector>
#include<list>

const int N=100010;
const int M=200020;

int n;

//vector< vector<int> > a;
vector <list <int> > a;
vector<bool> viz(N,false);

void citire(){
	int x,y,m;
	ifstream in("dfs.in");
	in>>n>>m;
	a.resize(n+1);
	/*
	vector<int> d(n,0);
	list< pair<int,int> > v;
	for(int i=0;i<m;++i){
		in>>x>>y;
		pair<int,int> p(x,y);
		v.push_back(p);
		++d[x];
		++d[y];
	}
	for(int i=1;i<=n;++i)
		a[i].reserve(d[i]);
	for(list< pair<int,int> >::iterator it=v.begin() ; it!=v.end() ; ++it){
		a[it->first].push_back( it->second );
		a[it->second].push_back( it->first );
	}
	*/
	for(int i=0;i<m;++i){
		in>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	in.close();
}

void df(int x){
	viz[x]=true;
	/*
	for(vector<int>::iterator i=a[x].begin() ; i!=a[x].end() ; ++i)
		if(!viz[*i])
			df(*i);
	*/
	for(list<int>::iterator i=a[x].begin() ; i!=a[x].end() ; ++i)
		if(!viz[*i])
			df(*i);
}

void rezolva(){
	ofstream out("dfs.out");
	int k=0;
	for(int i=1;i<=n;++i)
		if(!viz[i]){
			df(i);
			++k;
		}
	out<<k<<"\n";
	out.close();
}

int main(){
	citire();
	rezolva();
	return 0;
}