#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <limits>

class Graph {
public:
    Graph(const std::string &filename) {
        std::ifstream fin(filename);
        int n, m;
        fin >> n >> m;
        adj_list.resize(n + 1, std::vector<int>());

        int f, g, h;
        for (int i = 0; i < m; i++) {
            fin >> f >> g;
            adj_list[f].push_back(g);
            adj_list[g].push_back(f);
        }

        fin.close();
    }

    int num_conn_comp() {
        std::vector<bool> seen(adj_list.size());
        int k = 0;
        for (int i = 1; i < adj_list.size(); i++) {
            if (seen[i] == 0) {
                k++;
                dfs(i, seen);
            }
        }
        return k;
    }

private:
    void dfs(int i, std::vector<bool> &seen) {
        if (seen[i] == 1) return;
        seen[i] = 1;
        for (int e:adj_list[i])
            dfs(e, seen);
    }

private:
    std::vector<std::vector<int>> adj_list;


};

int main() {
    Graph graph("dfs.in");

    std::ofstream fout("dfs.out");
    fout << graph.num_conn_comp();
    fout.close();
}