#include<fstream>
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");

int n,m,viz[1000001];
struct nod{int info;
nod *next;
};

nod *LA[1000001];

void add(int x,int y){
	nod*n=new(nod);
	n->info=y;
	n->next=LA[x];
	LA[x]=n;
	n=new(nod);
	n->info=x;
	n->next=LA[y];
	LA[y]=n;
}

void citire(){
	int i,x,y;
	in>>n>>m;
	for(i=1;i<=m;i++){
		in>>x>>y;
		add(x,y);
	}
}

void df(int start){
	viz[start]=1;
	nod*nc=LA[start];
	while(nc){
		int y=nc->info;
		if(!viz[y]) df(y);
		nc=nc->next;
	}
}


int main(){
	citire();
	int i,c=0;
	for(i=1;i<=n;i++)
		if(!viz[i]){
			c++;
			df(i);
		}
	out<<c;
	return 0;
}