/*


      _             _    ___     ___    _  __       __
   __| |   __ _    / |  / _ \   / _ \  (_)/ /    _  \ \
  / _` |  / _` |   | | | | | | | | | |   / /    (_)  | |
 | (_| | | (_| |   | | | |_| | | |_| |  / /_     _   | |
  \__,_|  \__,_|   |_|  \___/   \___/  /_/(_)   (_)  | |
                                                    /_/


 */

//#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <set>
#include <algorithm>
#include <bitset>
#include <time.h>
#include <tuple>
#include <fstream>
#include <iomanip>
#include <utility>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/trie_policy.hpp>
#include <unordered_map>

#pragma warning "da 100% din tine. :)"
#define nl '\n'
#define cnl cout << '\n';
#define pb(x) push_back(x)
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define ll long long
#define ull unsigned ll

#define a first
#define b second
#ifdef INFOARENA
#define ProblemName "dfs"
#endif
#define MCONCAT(A, B) A B
#ifdef ProblemName
#define InFile MCONCAT(ProblemName, ".in")
#define OuFile MCONCAT(ProblemName, ".out")
#else
#define InFile "a.in"
#define OuFile "a.out"
#endif


//using namespace __gnu_pbds;
using namespace std;
ifstream cin(InFile);
ofstream cout(OuFile);


//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> indexed_set;
//typedef trie<string, null_type, trie_string_access_traits<>, pat_trie_tag, trie_prefix_search_node_update> pref_trie;

template<class v, class type>
void print(v Vector, type nr) {
    for_each(all(Vector), [](type x) {
        cout << x << ' ';
    });
}


typedef struct node {
    int index;
    node *adjlist;
} *vertex;

vertex v[100001];

bool vis[100001];

void add(vertex &target, int index) {
    vertex temp;
    temp = new node;
    temp->index = index;
    temp->adjlist = target;
    target = temp;
}

void dfs(int index) {
    vertex temp;
    vis[index] = true;
    for (vertex p = v[index]; p != NULL; p = p->adjlist) { //merg prin adjlist pt fiecare element
        if (vis[p->index] == 0)
            dfs(p->index); //daca nu am mai fost pe aici, apelez dfs pt indexul la care arata acest nod
    }
}

int main() {
    ios_base::sync_with_stdio(false);
//    clock_t tStart = clock();
    cin.tie(0);
    int x, y;
    int n, m;
    int cc = 0;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        cin >> x >> y;
        add(v[x], y);
        add(v[y], x);
    }
    for (int i = 1; i <= n; ++i) {
        if (vis[i] == 0) {
            //daca nu am mai fost aici inseamna ca nu a apartinut niciunei componente conexe
            ++cc;
            dfs(i);
        }
    }
    cout << cc << nl;
//    printf("\nTime taken: %.2fs\n", (double) (clock() - tStart) / CLOCKS_PER_SEC);
}