#include <fstream.h>
ifstream f("dfs.in");
ofstream g("dfs.out");
long n,m,x,y,cc=0,i;
int viz[100001];

struct nod{int a; nod *urm;};
nod * v[100001],*p;

void dfs(int x)
{
	viz[x]=1;
	nod *p=v[x];
	while(p)
	{
		if(viz[p->a]==0)
			dfs(p->a);
		p=p->urm;
	}
}

int main()
{	
	f>>n>>m;
	for(i=1;i<=m;i++)
	{
		f>>x>>y;
		p=new nod;
		p->a=y;
		p->urm = v[x];
		v[x]=p;
		
		p=new nod;
		p->a=y;
		p->urm=v[y];
		v[y]=p;
	}
	for(i=1;i<=n;i++)	
		if(viz[i]==0)cc++,dfs(i);
	g<<cc<<'\n';
	f.close();
	g.close();
	return 0;
}