#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

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

#define NMAX 100005

int n, m, nr;
vector<int> G[NMAX];
bitset<NMAX> viz;

void citire() {
    f >> n >> m;
    int n1, n2;
    for (int i = 0; i < m; ++i) {
        f >> n1 >> n2;
        G[n1].push_back(n2);
        G[n2].push_back(n1);
    }
}

void DFS(int nod) {
    viz.set(nod);
    for (auto &nod2:G[nod])
        if (!viz[nod2])
            DFS(nod2);
}

void parcurgere() {
    for (int i = 1; i <= n; ++i)
        if (!viz[i]) {
            nr++;
            DFS(i);
        }
}

int main() {
    citire();
    parcurgere();
    g << nr;
    return 0;
}