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

using namespace std;

vector<vector<int>> adj_list;
vector<bool> viz;
ifstream f ("dfs.in");
ofstream g ("dfs.out");
int N, M;

void read(){
    f >> N >> M;

    adj_list.resize(N + 1);
    viz.resize(N + 1);

    for(int x, y, i = 1; i <= N; i++) {
        f >> x >> y;
        adj_list[x].push_back(y);
        adj_list[y].push_back(x);
    }

}

int dfs(int start_node){
    viz[start_node] = true;
    vector<int>::iterator it;
    for (it = adj_list[start_node].begin(); it != adj_list[start_node].end(); ++it) {
        if(!viz[*it]){
            dfs(*it);
        }
    }
}

int main() {

    int number_of_components = 0;

    read();

    for (int i = 1; i <= N; ++i) {
        if(!viz[i]){
            dfs(i);
            number_of_components++;
        }
    }

    g << number_of_components << '\n';
    g.close();

    return 0;
}