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

using namespace std;

const int nMax = 100005;

int n, m;
vector<int> vecini[nMax];
int rasp = 0;
bool viz[nMax];

void citire()
{
    ifstream in("dfs.in");
    in >> n >> m;
    int x, y;
    for(int i = 1; i <= m; ++i)
    {
        in >> x >> y;
        vecini[x].push_back(y);
        vecini[y].push_back(x);
    }
    in.close();
}

void Fill(int current)
{
    viz[current] = true;
    for(auto v:vecini[current])
        if(viz[v] == false)
            Fill(v);
}

void rezolvare()
{
    for(int i = 1; i <= n; ++i)
        if(viz[i] == false)
        {
            Fill(i);
            rasp++;
        }
}

void afisare()
{
    ofstream out("dfs.out");
    out << rasp;
    out.close();
}

int main()
{
    citire();
    rezolvare();
    afisare();
    return 0;
}