#include <bits/stdc++.h>
using namespace std;

class Task {
public:
    void solve() {
        read_input();
        print_output(get_result());
    }

private:
    // numarul maxim de noduri
    static constexpr int NMAX = (int)1e5 + 5; // 10^5 + 5 = 100.005

    // n = numar de noduri, m = numar de muchii/arce
    int n, m;

    // adj[node] = lista de adiacenta a nodului node
    // exemplu: daca adj[node] = {..., neigh, ...} => exista muchia (node, neigh)
    vector<int> adj[NMAX];
    vector<int> parent;

    void read_input() {
        ifstream fin("dfs.in");
        fin >> n >> m;
        for (int i = 1, x, y; i <= m; i++) {
            fin >> x >> y; // muchie (x, y)
            adj[x].push_back(y);
            adj[y].push_back(x);
        }

        parent = vector<int>(NMAX, 0); // nodurile cu 0 sunt parinti

        fin.close();
    }

    int get_result() { 
        int result = 0;

        for (int i = 1; i <= n; i++) {
            if (!parent[i]) {
                result++;
                dfs(i);
            }
        }

        return result; 
    }

    void dfs(int node) {
        for (auto neigh : adj[node]) {
            // daca nu are parinte setat si nu e parinte 
            // seteaza parintele si continua parcugerea
            if (!parent[neigh] && parent[node] != neigh) {
                parent[neigh] = node;
                dfs(neigh);
            }
        }
    }

    void print_output(int result) {
        ofstream fout("dfs.out");
        fout << result << "\n";

        fout.close();
    }
};

int main() {
    auto* task = new (nothrow) Task();
    if (!task) {
        cerr << "new failed!\n";
        return -1;
    }
    task->solve();
    delete task;
    return 0;
}