#include <fstream>
#include <vector>
using namespace std;

void DFS(vector<int> v[], bool visited[], int node);

int main()
{
    int N, M, X, Y, i;
    ifstream f("dfs.in");
    f >> N >> M;

    vector<int> v[N + 1];
    bool visited[N + 1];
    for (i = 1; i <= N; i++)
        visited[i] = false;

    for (i = 1; i <= M; i++)
    {
        f >> X >> Y;
        v[X].push_back(Y);
        v[Y].push_back(X);
    }
    f.close();

    int k = 0;
    for (i = 1; i <= N; i++)
    {
        if (!visited[i])
        {
            DFS(v, visited, i);
            k++;
        }
    }

    ofstream g("dfs.out");
    g << k;
    g.close();

    return 0;
}

void DFS(vector<int> v[], bool visited[], int node)
{
    visited[node] = true;

    for (int i = 0; i < v[node].size(); i++)
        if (!visited[v[node][i]])
            DFS(v, visited, v[node][i]);
}