#include <fstream>
#include <vector>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");

const int nlim=100005;
int n,m,nr=0;
bool viz[nlim];
vector <int> muchii[nlim];

void DFS(int nod)
{
    viz[nod]=1;
    for(unsigned int i=0;i<muchii[nod].size();i++)
    {
        int vecin=muchii[nod][i];
        if(viz[vecin]==0)
            DFS(vecin);
    }
}

void citire()
{
    f>>n>>m;
    for(int i=1;i<=n;i++)
    {
        int x,y;
        f>>x>>y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }
}

int main()
{
    citire();
    for(int i=1;i<=n;i++)
    {
        if(viz[i]==0)
        {
            nr++;
            DFS(i);
        }
    }
    g<<nr;
    return 0;
}