#include <fstream>
#include <vector>
#define MAX 100000
using namespace std;

bool used[MAX + 1];
int n, m, components;
vector<int> L[MAX + 1];

void Read() {
    ifstream fin("dfs.in");
    fin >> n >> m;
    L = new vector<int>[n];
    int x, y;
    for(int i = 0; i < m; ++i) {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    fin.close();
}

void DFS(int k) {
    used[k] = true;
    vector<int>::iterator *it;
    for(it = L[k].begin(); it !=L[k].end(); ++it) {
        if(!used[*it]) {
            DFS(*it);
        }
    }
}

void Solve() {
    for(int i = 1; i <= n; ++i) {
        if(!used[i]) {
            ++components;
            DFS(i);
        }
    }
}

void Write() {
    ofstream fout("dfs.out");
    fout << components << "\n";
    fout.close();
}

int main() {
    Read();
    Solve();
    Write();
    return 0;
}