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

class Task {
public:
    static const string INPUT_FILE;
    static const string OUTPUT_FILE;

    // 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 arcul (node, neigh)
    vector<int> adj[NMAX];

    void solve() {
        readInput();
        writeOutput(getResult());
    }

private:
    void readInput() {
        ifstream fin(INPUT_FILE);
        fin >> n >> m;

        for (int node = 1; node <= n; node++) {
            adj[node].clear();
        }

        for (int i = 1, x, y; i <= m; i++) {
            // arc (x, y)
            fin >> x >> y;
            adj[x].push_back(y);
            adj[y].push_back(x);
        }

        fin.close();
    }

    void writeOutput(int result) {
        ofstream fout(OUTPUT_FILE);
        fout << result;
        fout.close();
    }

    void bfs(int node, vector<int>& visited) {
        queue<int> q;
        q.push(node);
        visited[node] = 1;

        while (!q.empty()) {
            int curr = q.front();
            q.pop();

            for (int neigh : adj[curr]) {
                if (visited[neigh] == 0) {
                    visited[neigh] = 1;
                    q.push(neigh);
                }
            }
        }
    }

    int getResult() {
        vector<int> visited(n + 1, 0);
        int result = 0;

        for (int node = 1; node <= n; node++) {
            if (visited[node] == 0) {
                bfs(node, visited);
                result++;
            }
        }

        return result;
    }
};

const string Task::INPUT_FILE = "dfs.in";
const string Task::OUTPUT_FILE = "dfs.out";

int main() {
    Task* task = new (nothrow) Task();
    if (!task) {
        cerr << "new failed: WTF are you doing? Throw your PC!\n";
        return -1;
    }
    task->solve();
    delete task;
    return 0;
}