#include<fstream>
#include<iostream>

using namespace std;

typedef struct nod
{
	int inf;
	nod *urm;
} NOD;
typedef NOD *graf[100010];
graf G;

int n,m,nr;
bool viz[100010];

void citire()
{
	ifstream f("dfs.in");
	f>>n>>m;
	int a,b;
	NOD *p;
	for(int i=1;i<=m;i++)
	{
		p=new NOD;
		f>>a>>b;
		p->inf=a;p->urm=G[b];G[b]=p;
		p=new NOD;
		p->inf=b;p->urm=G[a];G[a]=p;
	}
	f.close();
}

void dfs(int x)
{
	NOD *p;
	p=G[x];
	while(p)
	{
		if(!viz[p->inf])
		{
			viz[p->inf]=true;
			dfs(p->inf);
		}
		p=p->urm;
	}
}

int main()
{
	citire();
	for(int i=1;i<=n;i++)
		if(!viz[i])
		{
			dfs(i);
			nr++;
		}
	ofstream g("dfs.out");
	g<<nr<<'\n';
	g.close();
	return 0;
}