#include <bits/stdc++.h>

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;
void DFS(int nod);
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);
        }
    }
}
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);
        }
    }
}
int main()
{
    citire();
    fout<<insule;
    return 0;
}