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

using namespace std;

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

const int NMAX =100005;

int n,m;
bool vizitat[NMAX];
vector <int> muchii[NMAX];
int insule=0;

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 read()
{
    in>>n,m;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        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()
{
    read();
    out<<insule<<endl;
    return 0;
}