#include <vector>
#include <fstream>

using namespace std;

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

vector <int> v[100002];

int n, m, x, y, viz[100002], cont;

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

int  main() {
    fin >> n >> m;
    for (int i = 1; i <= m; i++) {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for (int i = 1; i <= n; i++) {
        while (not viz[i]) {
            cont++;
            dfs(i);
        }
    }
    fout << cont;
}