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

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

vector<vector<int>> adj; // Liste de adiacenta
vector<bool> visited;    // Vector de vizitare
int N, M;                // N = numarul de noduri, M = numarul de muchii

void dfs(int node)
{
    visited[node] = true;

    // Parcurgem vecinii nodului curent
    for (int neighbor : adj[node])
    {
        if (!visited[neighbor])
        {
            dfs(neighbor);
        }
    }
}

int count_components()
{
    int components = 0;

    // Parcurgem fiecare nod
    for (int i = 1; i <= N; i++)
    {
        if (!visited[i])
        {
            // Am gasit un nod nevizitat, deci o noua componenta conexa
            components++;
            dfs(i);
        }
    }

    return components;
}

int main()
{
    // Citim N si M
    fin >> N >> M;

    // Initializam listele de adiacenta si vectorul de vizitare
    adj.resize(N + 1);
    visited.resize(N + 1, false);

    // Citim muchiile si construim listele de adiacenta
    for (int i = 0; i < M; i++)
    {
        int x, y;
        fin >> x >> y;
        // Graful este neorientat, adaugam muchia in ambele directii
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    // Calculam si afisam numarul de componente conexe
    fout << count_components();

    fin.close();
    fout.close();
    return 0;
}