#include <iostream>
#include <fstream>
#include <vector>
#define VMAX 100000
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int V, E, x, y;
vector <int> adj[VMAX];
bool viz[VMAX];

void DFS(int u)
{
    viz[u] = true;

    for (int v = 0; v < adj[u].size(); v++)
        if (viz[adj[u][v]] == false) DFS(adj[u][v]);
}

int main()
{
    fin >> V >> E;

    for (int i = 0; i < E; i++)
    {
        fin >> x >> y;
        x--, y--;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    int nr_conexe = 0;

    for (int i = 0; i < V; i++)
        if (viz[i] == false) DFS(i), nr_conexe++;

    fout << nr_conexe;

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