# include <fstream.h>
ifstream f("dfs.in");
ofstream g("dfs.out");

struct nod{ int a; nod* urm;};
nod * v[100001],*p;
long i,m,n,x,y,nrc;
int viz[100001];// viz[i]=1=> am ajuns in i
void citire()
{
	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=x; p->urm=v[y];v[y]=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()
{
	citire();
	for(i=1;i<=n;i++) if(viz[i]==0){nrc++;dfs(i);}
	g<<nrc<<'\n';
	f.close();
	g.close();
	return 0;
}