#include <iostream>
#include <vector>

#include <fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
const int LIM=100005;
int N,M,insule=0;
vector <int> Muchii[LIM];

bool vizitat[LIM];
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++; DFS(i);}


}
int main()
{
    Citire();
    return 0;
}