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

void dfs(int x, vector<int> adjList[], bool visited[])
{
    visited[x] = true;
    for (int i = 0; i < adjList[x].size(); i++)
    {
        int neighbor = adjList[x][i];
        if (!visited[neighbor])
            dfs(neighbor, adjList, visited);
    }
}

int main()
{
    int N, M, X, Y;
    ifstream f("dfs.in");
    f >> N >> M;
    vector<int> adjList[N + 1];
    for (int i = 0; i < N; i++)
    {
        f >> X >> Y;
        adjList[X].push_back(Y);
        adjList[Y].push_back(X);
    }
    f.close();

    bool visited[N + 1];
    fill(visited + 1, visited + (N + 1), false);

    int result = 0;
    for (int i = 1; i <= N; i++)
        if (!visited[i])
        {
            result++;
            dfs(i, adjList, visited);
        }

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

    return 0;
}