#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream f ("dfs.in");
ofstream g ("dfs.out");
int N,M,nr;
int const Nmax=100001;
bool ok[Nmax]={false};
vector <int> Muchie[Nmax];

void MarcVecini(int nod)
{
    ok[nod]=true;
    for(unsigned int i=0;i<Muchie[nod].size();i++)
    {
        int vecin=Muchie[nod][i];
        if(ok[vecin]==false)
        {
            MarcVecini(vecin);
        }
    }


}
void citire()
{
    f>>N>>M;
    for(int i=1;i<=M;i++)
    {
        int x,y;
        f>>x>>y;
        Muchie[x].push_back(y);
        Muchie[y].push_back(x);

    }
    for(int i=1;i<=N;i++)
    {
          if(ok[i]==false)
          {
              nr++;
              MarcVecini(i);
          }
    }
}

int main()
{
    citire();
    g<<nr;

    return 0;
}