#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int n,m;
int nr;
int viz[100001];
vector <int> A[200001];
void dfs(int nod)
{
    viz[nod]=1;
    for(auto it:A[nod])
    {
        if(viz[it]==0)
            dfs(it);
    }
}
int main()
{
    fin>>n>>m;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        fin>>x>>y;
        A[x].push_back(y);
        A[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            dfs(i);
        }
    }
    fout<<nr;
    return 0;
}