#include <vector>
#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");

int n,m;
const int nlim = 100005;
bool vizitat[nlim];
vector < int > muchii[nlim];
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 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);
        }
    }
}
int main()
{
    citire();
    fout<<insule<<"\n";
    return 0;
}