#include <bits/stdc++.h>

using namespace std;

class graph {
    vector<vector<int>> gr;
    int n, m;
    vector<int> viz;

public:
    graph(vector<vector<int>> gr_, int n_, int m_) : gr(move(gr_)), n(n_), m(m_) {
        viz.resize(n + 1, 0);
    }
    graph() : n(0), m(0) {}

    void dfs (const int &start) {
        viz[start] = 1;
        for (auto vecin : gr[start]) {
            if (!viz[vecin]) dfs(vecin);
        }
    }

    int nr_comp() {
        int nr_comp = 0;
        for (int i = 1; i <= n; ++i) {
            if (!viz[i]) {
                ++nr_comp;
                dfs(i);
            }
        }
        viz.resize(n + 1, 0);
        return nr_comp;
    }
};

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

    int n, m;
    f >> n >> m;
    vector<vector<int>> grf(n + 1);
    for (int i = 0; i < m; ++i) {
        int x, y;
        f >> x >> y;
        grf[x].push_back(y);
        grf[y].push_back(x);
    }

    graph graf(grf, n, m);

    g << graf.nr_comp();
    g.close();
    return 0;
}