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

#define N 100005

using namespace std;

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

vector < int > L[N];
bool viz[N];
int n, m;
int s;

void adaugareElemente()
{
    int x, y;
    fin >> n >> m;
    for(int i = 1; i <= n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS(int k)
{
    viz[k] = 1;
    for(short i = 0; i < L[k].size(); i++)
        if(!viz[L[k][i]])
            DFS(L[k][i]);
}

int main()
{
    adaugareElemente();
    for(int i = 1; i <= n; i++)
    {
        if(!viz[i]) ++s;
        DFS(i);
    }
    fout << s << "\n";
    return 0;
}