/*
  Lefter Sergiu - 16/02/2023
*/
#include <fstream>
#include <vector>

using namespace std;

ifstream in("dfs.in");
ofstream out("dfs.out");

const int N = 100000;

int n, m, viz[N+1], cnt;
vector<int> a[N+1];

void DFS(int nod) {
    viz[nod] = 1;
    for (auto i: a[nod]) {
        if (!viz[i]) {
            DFS(i);
        }
    }
}

int main() {
    in >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for (int i = 1; i <= n; ++i) {
        if (!viz[i]) {
            cnt++;
        }
    }
    out << cnt;
    in.close();
    out.close();
    return 0;
}