#include<fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int k,n,m,viz[100001];
typedef struct nod {nod *urm; int la;}NOD;
NOD *p[100001];
void add(int x, int y)
{
	nod *q=new nod;
	q->la=y;
	q->urm=p[x];
	p[x]=q;
	nod *t=new nod;
	t->la=x;
	t->urm=p[y];
	p[y]=t;
}
void citire()
{
	f>>n>>m;
	for (int i=1;i<=m;i++)
	{
		int x,y;
		f>>x>>y;
		add(x,y);
	}
}
void dfs(int i)
{
	viz[i]=1;
	for (nod *q=p[i];q;q=q->urm) if (viz[q->la]==0)	dfs(q->la);
}
int main()
{
	citire();
	for (int i=1;i<=n;i++)
		if (viz[i]==0) 
		{
			k++;
			dfs(i);
		}
	g<<k;
	return 0;
}