#include <iostream>
#include <vector>
#include <queue>
#include <fstream>
#include <unordered_map>
using namespace std;

class Graph {
    //private attributes
    vector<vector<int>> edges;
    int numberOfNodes;

    //-------------------------------------

    //private methods
    void DFS(unordered_map<int, bool>&, int);
public:
    Graph(int);
    ~Graph();
    void setEdge(int, int);
    vector<int> distance(int);
    int numberOfComponents();
    void displayEdges();
};


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

//    int numberOfNodes, numberOfEdges, start, from, to;

//    in >> numberOfNodes >> numberOfEdges >> start;

    int numberOfNodes, numberOfEdges, from, to;

    in >> numberOfNodes >> numberOfEdges;

    Graph* graph = new Graph(numberOfNodes);

    for (int countEdge = 1; countEdge <= numberOfEdges; countEdge++) {
        in >> from >> to;
        graph->setEdge(from, to);
        graph->setEdge(to, from);
    }

//    graph->displayEdges();

    out << graph->numberOfComponents();
//    vector<int> distance = graph->distance(start);

//    for (int i = 1; i < distance.size(); i++) {
//        out << distance[i] << " ";
//    }

    return 0;
}

void Graph::displayEdges() {
    for(int node = 1; node <= this->numberOfNodes; node ++) {
        for (auto edge: this->edges[node])
            cout << node << " " << edge << endl;
    }
}

Graph::Graph(int numberOfNodes) {
    this->numberOfNodes = numberOfNodes;
    this->edges.resize(numberOfNodes + 1);
}

Graph::~Graph() {}

void Graph::setEdge(int from, int to) {
    this->edges[from].push_back(to);
}

vector<int> Graph::distance(int from) {
    queue<int> queue;
    vector<int> visited(this->numberOfNodes + 1, -1);

    visited[from] = 0;
    queue.push(from);

    while (!queue.empty()) {
        int node = queue.front();
        for (auto edge : this->edges[node]) {
            if (visited[edge] == -1) {
                visited[edge] = visited[node] + 1;
                queue.push(edge);
            }
        }
        queue.pop();
    }

    return visited;
}

void Graph::DFS(unordered_map<int, bool> &visited, int start) {
    visited[start] = true;

    for(int node = 0; node < edges[start].size(); node ++) {
        if(!visited[edges[start][node]]) {
            DFS (visited ,edges[start][node]);
        }
    }
}

int Graph::numberOfComponents() {
    unordered_map<int ,bool> visited;
    int nrOfComp = 0;

    for(int node = 1; node <= this->numberOfNodes; node ++) {
        if(visited[node] == 0) {
            nrOfComp ++;
            this->DFS(visited, node);
        }
    }
    return nrOfComp;
}