#include <fstream>
#include <utility>
#include <vector>

class graf {
    int n, m;
    std::vector<int> sel;
    std::vector<std::vector<int>> lista;

public:
    graf(int n, int m, std::vector<std::vector<int>> lista) : n(n), m(m), lista(std::move(lista)) {
        sel.resize(n + 1, 0);
    }
    graf() : n(0), m(0) {}

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

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

int main()
{
    std::ifstream fin("dfs.in");
    std::ofstream fout("dfs.out");

    int n, m;
    fin >> n >> m;

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

    graf meow(n, m, lista);

    fout << meow.nr_comp();

    return 0;
}