#include <iostream>
#include <fstream>
#include <list>
#include <vector>
#include <algorithm>

using namespace std;

void dfs (int x, int n, vector<bool>& vis, vector<int> adj[])
{
   // list<int>::iterator it;
    vis[x] = true;
   // for (it = adj[x].begin(); it != adj[x].end(); ++it)
    for (int i = 0; i < adj[x].size(); ++i)
    {
        if (!vis[adj[x][i]])
        {
            dfs (adj[x][i], n, vis, adj);
        }
    }
}
    
int main()
{
    int nrConexe = 0;
    int m, n, i, x, y;
    //list<int> adj;
    ifstream fin("dfs.in");
    ofstream fout("dfs.out");
    fin >> n;
    fin >> m;
    vector<int> adj[n + 1];
    vector<bool> vis(n + 1);
    for (i = 0 ;i<=n-1;i++)
        vis[i]=false;
    for (i = 0 ; i <= m-1; i++)
    {
        fin>>x;
        fin>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    
    for (i = 0; i <= n-1 ;i++)
    {
        //cout<<i<<"     ";
        //for (int j=0;j<=n-1;j++)
          //  cout<<vis[j]<<" ";
        //cout<<endl;
        if (!vis[i + 1])
        {
            ++nrConexe;
            dfs(i + 1, n, vis, adj);
        }
    }
    fout<<nrConexe;
    fin.close();
    fout.close();
    return 0;
}