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

using namespace std;

void dfs (int x, int n, vector<int>& vis, list<int> adj[])
{
    //vector<int> vis[n];
    list<int>::iterator it;
    vis[x] = 1;
   // if (adj[x].empty())
     //   return;
    for (int i = 0; i <= n - 1; i++)
    {
        it = find(adj[x].begin(), adj[x].end(), i);
        if (it != adj[x].end() && !vis[i])
        {
            //cout<<i<<"aici\n";
            dfs (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;
    list<int> adj[n];
    vector<int> vis(n);
    //cout<<"CITIRE:  \n";
    //cout<<m<<" "<<n;
    for (i = 0 ; i <= m-1; i++)
    {
        fin>>x;
        fin>>y;
        //cout<<x<<" "<<y<<endl;
        //cout<<x<<" "<<y<<endl;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    
    for (i = 0; i <= n-1 ;i++)
    {
       // for(int j = 0; j<=n-1;j++)
         //   cout<<vis[j]<<" ";
       // cout<<"\n";
        if (!vis[i])
        {
            //cout<<nrConexe<<" ";
            ++nrConexe;
            //cout<<"IN MAIN!!!!!!!!!!!!\n";
            dfs(i, n, vis, adj);
        }
    }
    fout<<nrConexe;
    fin.close();
    fout.close();
    return 0;
}