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

std::ofstream fout("dfs.out");

void Citire();
void DFS(int Nod);

bool vizitat[100005];

int n, m, x, y;
std::vector < int > Muchii[100005];
int insule;

int main()
{
    Citire();
    fout << insule << '\n';
}

void Citire()
{
    std::ifstream fin("dfs.in");

    fin >> n >> m;
    for(int i = 1; i <= n; ++i)
    {
        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);
        }
}

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);
    }
}