#include <fstream>
#include <list>
#include <vector>


void dfs(int node_nr,
         const std::vector< std::list<int> > &graph,
         std::vector<bool> &visited)
{
    visited[node_nr] = true;
    for (auto &i : graph[node_nr])
        if (!visited[i])
            dfs(i, graph, visited);
}

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

    int N, M;
    in >> N >> M;

    std::vector< std::list<int> > graph(N+1);

    for (int i = 0; i < M; ++i) {
        int x, y;
        in >> x >> y;

        graph[x].push_front(y);
        graph[y].push_front(x);
    }

    std::vector<bool> visited_nodes(N+1, false);
    int count = 0;
    for (int i = 1; i <= N; ++i)
        if (!visited_nodes[i]) {
            ++count;
            dfs(i, graph, visited_nodes);
        }

    out << count;

    in.close();
    out.close();

    return 0;
}