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

using namespace std;

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

vector < vector < int> > adj;
vector <int> viz;

void DFS(int nod){
    viz[nod] = 1;
    for(int i : adj[nod])
        viz[i] = 1;

}

int nr = 0;
int n,m;

int main()
{
    fin>>n >>m;

    adj.resize(n+5);
    viz.resize(n+5);

    for(int i = 1; i<=m; i++)
    {
        int x, y;
        fin>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }

    for (int i = 1; i<=n; i++){
        if(viz[i]==0)
            nr++;
        DFS(i);
    }
    fout<<nr;

    return 0;
}