#include<fstream>
using namespace std;
int y,x,rez;
bool viz[100005];
ifstream cin("dfs.in"); 
ofstream cout("dfs.out");
typedef struct nod{
	int info;
	nod* next;
} *graf;
graf A[100005];

void add(graf &p,int x){
	graf m;
	m= new nod;
	m->info=x;
	m->next=p;
	p=m;
	
}
void dfs(int x){
	graf p;
	viz[x]=1;
	for(p=A[x];p!=NULL;p=p->next){
		if(!viz[p->info])dfs(p->info);
	} 
	
}
int main(){
int n,m;
cin>>n>>m;
	while(m--){
	cin>>x>>y;
	add(A[x],y);
	add(A[y],x);
}
for(int i=1;i<=n;i++){if(!viz[i]){rez++;dfs(i);}}
cout<<rez;
}