#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

const char iname[]="dfs.in";
const char oname[]="dfs.out";

static const int MAXN = 100005;

vector <int> adj[MAXN], viz;

void citeste_in(vector <int> *adj , int &n)
{
    int nrMuchii, x, y;
    ifstream in(iname);
    in>>n>>nrMuchii;
    for(; nrMuchii >= 0; nrMuchii--)
    {
        in>>x>>y;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    in.close();
}
void DFS(int nod, int tata_nod, int nr)
{
    vector <int>::iterator it;
    viz[nod] = nr;
    for(it = adj[nod].begin(); it != adj[nod].end(); ++it)
        if(*it != tata_nod)
            if(!viz[*it])
                DFS(*it, nod, nr+1);
}
int main()
{
    int n, cont = 0;
    citeste_in(adj, n);
    viz.resize(n+1);
    viz.assign(n+1, 0);
    for(int i = 1; i <= n; i++)
    {
        if(!viz[i])
            {
                DFS(i, 0, 0);
                cont++;
            }
    }
    ofstream out(oname);
    out<<cont;
    out.close();
    return 0;
}