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

using namespace std;

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

class Graph
{
    vector<vector<int>> adj;
    int nrNoduri, nrCompConexe;
public:
    Graph(int n) { adj = vector<vector<int>>(n); nrCompConexe = 0; nrNoduri = n;}
    ~Graph() { }
    void addEdge(int x, int y);
    void DFS();
    void utilDFS(int i, bool visited[]);
};

void Graph::addEdge(int x, int y)
{
    adj[x].push_back(y);
    adj[y].push_back(x);
}

void Graph::DFS()
{
    bool *visited = new bool[nrNoduri];
	for(int i = 0; i < nrNoduri; ++i)
		visited[i] = false;

	for (int i = 0; i < nrNoduri; ++i)
	{
		if (visited[i] == false)
		{
		    nrCompConexe++;
			utilDFS(i, visited);
		}
	}
    fout << nrCompConexe;
}

void Graph::utilDFS(int i, bool visited[])
{
    visited[i] = true;

	for(auto k : adj[i])
		if(visited[k] == false)
			utilDFS(k, visited);
}

int main()
{
    int n, m, x, y;
    fin >> n >> m;
    Graph g(n);
    for(int i=0; i<m; ++i)
    {
        fin >> x >> y;
        x--; y--;
        g.addEdge(x, y);
    }
    g.DFS();
    return 0;
}