/*
Alexandru Enache
Grupa 252
*/

#include <bits/stdc++.h>
using namespace std;


//ifstream fin("input"); ofstream fout("output");
ifstream fin("dfs.in"); ofstream fout("dfs.out");


class Graph{

private:

    int m_nodes;
    vector < vector < int > > m_gr;

public:

    Graph(int nodes, vector < vector < int > > &gr){
        m_nodes = nodes;
        m_gr = gr;
    }

    vector < int > bfs(int start){
        queue < int > q;
        vector < int > dist(m_nodes, -1);

        dist[start] = 0;
        q.push(start);

        while (!q.empty()){
            int now = q.front();
            q.pop();

            for (auto &x : m_gr[now]){
                if (dist[x] == -1){
                    dist[x] = dist[now] + 1;
                    q.push(x);
                }
            }
        }

        return dist;
    }

    void dfs(int node, vector < bool > &used){
        used[node] = true;
        for (auto &x: m_gr[node]){
            if (!used[x]){
                dfs(x, used);
            }
        }
    }

    int comp_conex_dfs(){

        int cont = 0;
        vector < bool > used(m_nodes, false);
        for (int i=0; i<m_nodes; i++){
            if (!used[i]){
                dfs(i, used);
                cont++;
            }
        }

        return cont;
    }

};


void solve() {

    ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

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

    vector < vector < int > > gr(n);

    for (int i=1; i<=m; i++){
        int a, b;
        fin>>a>>b;
        a--;
        b--;
        gr[a].push_back(b);
        gr[b].push_back(a);
    }

    Graph graph = Graph(n, gr);

    int comp_conex = graph.comp_conex_dfs();

    fout<<comp_conex<<'\n';

}


int main() {

    solve();

    return 0;
}