#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

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

const int a = 100001;
vector <int> z[a];
int n, m;
bool v[a];
int insule = 0;
void dfs(int Nod)
{
    v[Nod] =true;
    for (unsigned int i= 0; i<z[Nod].size();i++){
        int Vecin =  z[Nod][i];
        if (!v[Vecin])
            dfs(Vecin);
    }
}
int main()
{
    f>>n>>m;
    for(int i=1; i<=n; i++)
    {
        int x,y;
        f>>x>>y;
        z[x].push_back(y);
        z[y].push_back(x);
    }
    for(int i=1; i<=n;i++){

        if(!v[i]){
            insule+=1;
            dfs(i);
        }
    }
    g<<insule;
    return 0;
}