#include <iostream>
#include <fstream>
using namespace std;
const int NMAX=100001;
struct nod
{
    int x;
    nod *next;
};
nod *L[NMAX]; ///L[i]=lista vecinilor nodului i
int N,M,nrCC;
bool viz[NMAX];
ifstream f("dfs.in");
ofstream g("dfs.out");
void add_nod(int x,int y)///La lista vecinilor lui x se ad y
{
    nod *p=new nod;
    p->x=y;
    p->next=L[x];
    L[x]=p;
}
void citire()
{
    int x,y;
    f>>N>>M;
    for(int i=1;i<=M;i++)
    {
        f>>x>>y;
        add_nod(x,y);///Se adauga y la lista vecinilor lui x
        add_nod(y,x);///Se adauga x la lista vecinilor lui y
    }
}
void DFS(int i)
{
    viz[i]=1;
    for(nod *p=L[i];p!=NULL;p=p->next)
        if(viz[p->x]==0)
            DFS(p->x);
}
void comp_conexe()
{
    for(int i=1;i<=N;i++)
        if(viz[i]==0)
    {
        nrCC++;
        DFS(i);
    }
}
int main()
{
    citire();
    comp_conexe();
    g<<nrCC;
    f.close();
    g.close();



}