#include <fstream>
#include <vector>

using namespace std;

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

const int NMAX = 100001;
int n, m, insule = 0;

bool vizitat[NMAX];
vector <int> Muchii[NMAX];

void DFS(int nod)
{
    int vecin;
    vizitat[nod] = 1;
    for (unsigned int i = 0; i < Muchii[nod].size(); ++i)
    {
        vecin = Muchii[nod][i];
        if (!vizitat[vecin])
            DFS(vecin);
    }
}

void citire()
{
    int x, y;
    in >> n >> m;
    for (int i = 1; i <= n; ++i)
    {
        in >> x >> y;
        Muchii[x].push_back(y);
        Muchii[y].push_back(x);
    }
    for (int i = 1; i <= n; ++i)
    {
        if (!vizitat[i])
        {
            ++insule;
            DFS(i);
        }
    }
}

int main()
{
    citire();
    out << insule;
    return 0;
}