#include<algorithm>
using namespace std;

#define DIM 100001

int n,m,nrsol,c[DIM],f[DIM];

struct nod{
    int x;
    nod *urm;};
nod *lst[DIM];

void add(int a,int b){
    nod *p=new nod;
    
    p->x=b;
    p->urm=lst[a];
    lst[a]=p;}

void df(int a){
    nod *p;
    
    f[a]=1;
    for(p=lst[a]; p; p=p->urm)
        if(p->x&&!f[p->x]){
            f[p->x]=1;
            df(p->x);}}

void solve(){
    int i,x0,y0;
    
    scanf("%d%d",&n,&m);
    for(i=0; i<m; ++i){
        scanf("%d%d",&x0,&y0);
        add(x0,y0);
        add(y0,x0);}
    for(i=1; i<=n; ++i)
        if(!f[i]){
            ++nrsol;
            df(i);}
    printf("%d",nrsol);}

int main(){
    
    freopen("dfs.in","r",stdin);
    freopen("dfs.out","w",stdout);
    
    solve();
    return 0;}