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

int n,m,nrc,viz[100005];
vector<int> la[100005];

ofstream fout("dfs.out");

void citire(char* nume, int& n, int& m, vector<int>la[100005])
{
    ifstream fin(nume);
    fin >> n >> m;
    for (int i=1; i<=m; i++)
    {
        int x, y;
        fin >> x >> y;
        la[x].push_back(y);
        la[y].push_back(x);
    }
    fin.close();
}

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

int main()
{
    citire("dfs.in", n, m, la);
    for (int i=1; i<=n; i++)
    {
        if (viz[i] == 0) {
            nrc++;
            dfs(i);
        }
    }
    fout << nrc;
    fout.close();
    return 0;
}