#include <fstream>
#include <iostream>
#include <vector>
using namespace std;
ifstream fin("dfs.in");
ofstream fout("dfs.out");
int N, M;
vector<vector<int>> gr;
vector<bool> t;
void read() {
    int x, y;
    fin >> N >> M;
    gr.resize(N + 1);
    t.resize(N + 1, 0);
    for (int i = 0; i < M; ++i) {
        fin >> x >> y;
        gr[x].push_back(y);
        gr[y].push_back(x);
    }
}
void DFS(int nod) {
    t[nod] = true;
    for (auto i : gr[nod]) {
        if (!t[i]) {
            DFS(i);
        }
    }
}
int main()
{
    read();
    int con = 0;
    for (int i = 1; i <= N; ++i) {
        if (t[i] == false) {
            DFS(i);
            ++con;
        }
    }
    fout << con << "\n";
    return 0;
}