#include <algorithm>
#include <fstream>
#include <vector>

void dfs(const int source, const std::vector<std::vector<int>> &G, std::vector<bool> &V)
{
    V[source] = true;
    for (const int u : G[source])
        if (!V[u])
            dfs(u, G, V);
}

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

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

    std::vector<std::vector<int>> G(n, std::vector<int>());
    int u, v;
    while (m--)
    {
        fin >> u >> v;
        G[u - 1].push_back(v - 1);
        G[v - 1].push_back(u - 1);
    }

    int components = 0;
    std::vector<bool> V(G.size(), false);
    for (int source = 0; source < G.size(); ++source)
        if (!V[source])
        {
            dfs(source, G, V);
            components++;
        }

    fout << components << std::endl;

    return 0;
}