#include <cmath>
#include <iostream>
#include <vector>
#include <algorithm>
#include <string>
#include <set>
#include <map>
#include <list>
#include <time.h>
#include <math.h>
#include <random>
#include <deque>
#include <queue>
#include <cassert>
#include <unordered_map>
#include <unordered_set>
#include <iomanip>
#include <bitset>
#include <sstream>
#include <chrono>
#include <cstring>
#include <fstream>

using namespace std;


typedef long long ll;

const ll mod = 1e9 + 7;

vector<vector<int>> a;
vector<bool> flag;
vector<vector<int>> c;

void dfs(int v){
    flag[v] = true;
    c.back().push_back(v + 1);
    for(int u : a[v]){
        if(!flag[u])
            dfs(u);
    }
}

int main()
{
    fstream in;
    in.open("input.txt", ios::out);
    int n, m;
    in >> n >> m;
    a.resize(n);
    flag.resize(n);
    for(int i = 0; i < m; ++i){
        int v, u;
        cin >> v >> u;
        --v; --u;
        a[v].push_back(u);
        a[u].push_back(v);
    }
    for(int i = 0; i < n; ++i){
        if(!flag[i]){
            c.push_back({});
            dfs(i);
        }
    }
    cout << c.size() << "\n";

}