#include <iostream>
#include <fstream>
#include <queue>
#include <vector>
#include <limits.h>
#define NMAX 100001
///DFS.
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
int n,m,i,x,y,insule;
vector <int> v[NMAX];
bool vizitat[NMAX];
void Citire()
{
    f>>n;
    f>>m;
    for(i=1;i<=n;i++)
    {
        f>>x;
        f>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
}
void Rezolvare(int Start)
{
    int Curent;
    vizitat[Start]=true;
    for(size_t i=0;i<v[Start].size();i++)
    {
        Curent=v[Start][i];
        if(vizitat[Curent]==false)
            Rezolvare(Curent);
    }
}
int main()
{
    Citire();
    for(i=1;i<=n;i++)
    {
        if(vizitat[i]==false)
        {
            insule++;
            Rezolvare(i);
        }
    }
    g<<insule;

    return 0;
}