#include <fstream>
#include <vector>
#include <algorithm>
#include <cstring> 
 
class Graf
{
private:
    static constexpr int NMAX = 100009;
    const int N, M;
    std::vector<int> Adiacenta[NMAX];  // liste de adiacenta
 
public:
    Graf(int, int);
    void AdMuchie(int, int);
    void Bfs(int, int*);
    int Dfs();
 
    static constexpr int getNMAX() { return Graf::NMAX; }

private:
    void Dfs_fHelper(int, bool*);
};
 
Graf::Graf(int n, int m)
    : N(n), M(m)
{
}
 
void Graf::AdMuchie(int ini, int fin)
{
    Adiacenta[ini].push_back(fin);    
}
 
void Graf::Bfs(int S, int* nrArce)
{
    int coada[NMAX], st = 0, dr = 0;
 
    for (int i = 1; i <= N; ++i)
        nrArce[i] = -1;
    nrArce[S] = 0;
    coada[st] = S;
    while (st <= dr)
    {
        int curent = coada[st++];
        for (auto it = Adiacenta[curent].begin(); it != Adiacenta[curent].end(); ++it)
            if(nrArce[*it] == -1)
            {
                coada[++dr] = *it;
                nrArce[*it] = nrArce[curent] + 1;
            }
    }
}

int Graf::Dfs()
{
    bool vizitat[NMAX];
    int nrComp = 0;

    memset(vizitat, 0, NMAX * sizeof(bool));
    for (int i = 1; i <= N; ++i)
        if (!vizitat[i])
        {
            ++nrComp;
            Dfs_fHelper(i, vizitat);
        }

    return nrComp;
}

void Graf::Dfs_fHelper(int curent, bool* vizitat)
{
    vizitat[curent] = true;
    for (auto it = Adiacenta[curent].begin(); it != Adiacenta[curent].end(); ++it)
        if (!vizitat[*it])
            Dfs_fHelper(*it, vizitat);
}

 
int main()
{   
    std::ifstream f("dfs.in");
    std::ofstream g("dfs.out");
    int N, M;
 
    f >> N >> M;
    Graf graf(N, M);
    for (int x, y, i = 0; i < M; ++i)
    {
        f >> x >> y;
        graf.AdMuchie(x, y);
        graf.AdMuchie(y, x);
    }

    g << graf.Dfs();
 
    return 0;
}