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

int n,m,v[100001],cc=0;

struct nod{
	int info;
	nod *next;
};

nod *la[100001];

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

void bf(int start){
	v[start]=cc;
	nod *nc=la[start];
	while(nc){
		int y=nc->info;
		if(!v[y])
			bf(y);
		nc=nc->next;
	}
}

int main(){
	citire();
	for(int i=1; i<=n; i++)
		if(!v[i]){
			cc++;
			bf(i);
		}
	out<<cc;
	return 0;
}