#include <iostream>
#include <fstream>
#include <vector>
#include <unordered_set>

using namespace std;

class Graph {
public:
    int N; // Numărul de noduri
    vector<vector<int>> adjacencyList;

    Graph(int n) : N(n), adjacencyList(n) {}

    void addEdge(int u, int v) {
        adjacencyList[u].push_back(v);
        adjacencyList[v].push_back(u);
    }
};

void DFS(const Graph& graph, int node, unordered_set<int>& visited) {
    visited.insert(node);

    for (int neighbor : graph.adjacencyList[node]) {
        if (visited.find(neighbor) == visited.end()) {
            DFS(graph, neighbor, visited);
        }
    }
}

int numarComponenteConexe(const Graph& graph) {
    unordered_set<int> visited;
    int componenteConexe = 0;

    for (int node = 0; node < graph.N; ++node) {
        if (visited.find(node) == visited.end()) {
            DFS(graph, node, visited);
            componenteConexe++;
        }
    }

    return componenteConexe;
}

int main() {
    ifstream infile("dfs.in");
    ofstream outfile("dfs.out");

    if (!infile || !outfile) {
        cerr << "Nu s-a putut deschide fisierul de intrare/iesire.\n";
        return 1;
    }

    int N, M;
    infile >> N >> M;

    Graph graph(N);

    // Citirea muchiilor
    for (int i = 0; i < M; ++i) {
        int X, Y;
        infile >> X >> Y;
        graph.addEdge(X - 1, Y - 1); // Graful este indexat de la 0
    }

    int rezultat = numarComponenteConexe(graph);

    // Afisarea rezultatului in fisierul de iesire
    outfile << rezultat << endl;

    infile.close();
    outfile.close();

    return 0;
}