#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("dfs.in");
ofstream fout("dfs.out");

struct nod
{
    int vf;
    nod *urm;
}*v[100005];

int n,m,viz[100005],nr;

void citire()
{
    fin>>n>>m;
    int i,x,y;
    nod *p,*q;
    for(i=1;i<=n;++i)
        v[i]=NULL;
    for(i=1;i<=m;++i)
    {
        fin>>x>>y;
        p=new nod;
        p->vf=x;
        p->urm=v[y];
        v[y]=p;
        q=new nod;
        q->vf=y;
        q->urm=v[x];
        v[x]=q;
    }
}

void df(int x,int nr)
{
    viz[x]=nr;
    for(nod *q=v[x];q;q=q->urm)
        if(viz[q->vf]==0)
            df(q->vf,nr);
}

int main()
{
    citire();
    int i;
    for(i=1;i<=n;++i)
        if(viz[i]==0)
    {
        ++nr;
        df(i,nr);
    }
    fout<<nr;
    return 0;
}