#include <fstream>
#include <vector>
using namespace std;
ofstream fout ("dfs.out");
int n, m, viz[100005], cc=0;
vector <int> la[100005];
void citire(const 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])
            dfs(vecin);
    }
}
int main()
{
    citire("dfs.in", n, m, la);
    for (int i=1; i<=n; i++)
    {
        if (!viz[i]) {
            cc++;
            dfs(i);
        }
    }
    fout << cc;
    fout.close();
    return 0;
}