#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

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

class Graf{
private:
    int Nr_Noduri, Nr_Muchii;
    vector < vector<int> > matrice_adiacenta;
    
public:
    Graf(int N, int M, vector< vector<int> > & matrice); // constructor
    vector < vector<int> > getMatriceAdiacenta()
    {
        return matrice_adiacenta;
    }

    void Citire_Graf_Neorientat();
    void DFS(int nod_Start, vector<bool> &vizitat);
    void Numar_Comp_Conexe();
};

// constructor
Graf :: Graf(int N, int M, vector < vector<int> > & matrice)
{
    Nr_Noduri = N;
    Nr_Muchii = M;
    matrice_adiacenta = matrice;
}

void Graf :: Citire_Graf_Neorientat()
{
    for ( int i = 1; i <= Nr_Muchii; i++ )
    {
        int x, y;
        fin >> x >> y;
        matrice_adiacenta[x].push_back(y);
        matrice_adiacenta[y].push_back(x);
    }
}

void Graf :: DFS(int S, vector<bool> &vizitat)
{
    vizitat[S] = 1;
    for ( int i = 1; i < matrice_adiacenta[S].size(); i++ )
        if ( ! vizitat[matrice_adiacenta[S][i]] )
            DFS(matrice_adiacenta[S][i], vizitat);
}

void Graf :: Numar_Comp_Conexe()
{
    int nr_comp_conexe = 0;
    vector<bool> vizitat(Nr_Noduri+1, 0);
    for ( int i = 1; i <= Nr_Noduri; i++ )
        if ( !vizitat[i] )
        {
            nr_comp_conexe++;
            DFS(i, vizitat);
        }
    fout << nr_comp_conexe;
}

int main()
{
    int N, M;
    fin >> N >> M;
    
    vector < vector<int> > matrice;
    vector <int> aux(1,-1);
    matrice.resize(N+1, aux);

    Graf G(N, M, matrice);
    G.Citire_Graf_Neorientat();

    G.Numar_Comp_Conexe();

    return 0;
}