#include <iostream>
#include <fstream>
using namespace std;

ifstream f("dfs.in");
ofstream g("dfs.out");

int cnt, N, M;
int viz[100005];
typedef struct nod
{
    int x;
    nod *a;
}*pNod;
pNod v[100005];

void citire();
void ADD(int, int);
void DFS(int);
int main()
{
    citire();
    int i;
    for(i=1; i<=N; i++)
        if(!viz[i])
        {
            ++cnt;
            DFS(i);
        }
    g<<cnt;
    return 0;
}
void ADD(pNod &dest, int val)
{
    pNod p;
    p=new nod;
    p->x=val;
    p->a=dest;
    dest=p;
}
void citire()
{
    ///int N, M;
    f>>N>>M;
    int i, X, Y;
    for(i=1; i<=M; i++)
    {

        f>>X>>Y;
        ADD(v[X],Y);
        ADD(v[Y],X);

    }
}
void DFS(int nod)
{
    pNod p;
    viz[nod]=1;
    for(p=v[nod]; p!=NULL ; p=p->a)
        if(!viz[p->x])
            DFS(p->x);

}