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

using namespace std;

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

const int NLIM = 100005;

int N, M;
bool vizitat[NLIM];

vector < int > Muchii[NLIM];

int insule = 0;
/*
 * 1: 2 4
 * 2: 1
 * 3: 5
 * 4: 1
 * 5: 3
 * 6: -
 */

void DFS(int Nod)
{
    vizitat[Nod] = true;
    for(unsigned int i = 0; i < Muchii[Nod].size(); i++)
    {
        int Vecin = Muchii[Nod][i];
        if(!vizitat[Vecin])
            DFS(Vecin);
    }
}

void Citire()
{
    fin >> N >> M;
    for(int i = 1; i <= N; i++)
    {
        int x, y;
        fin >> x >> y;
        Muchii[x].push_back(y);
        Muchii[y].push_back(x);
    }
    for(int i = 1; i <= N; i++)
    {
        if(!vizitat[i]) {
            insule += 1;
            DFS(i);
        }
    }
}

int main() {
    Citire();
    fout << insule << "\n";
    return 0;
}