#include <fstream>
using namespace std;

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

struct nod {
    int vf;
    nod *urm;
};
nod* v[100001];
int n, m, viz[100001], k;

void add(nod *&prim, int x) {
    nod *q = new nod;
    q->vf = x;
    q->urm = prim;
    prim = q;
}

void read() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        v[i] = nullptr;
    }
    for (int i = 1; i <= m; i++) {
        int x, y;
        cin >> x >> y;
        add(v[x], y);
        add(v[y], x);
    }
}

void dfs(int p) {
    viz[p] = k;
    for (nod *q = v[p]; q; q = q->urm) {
        if (viz[q->vf] == 0)
            dfs(q->vf);
    }
}
int main() {
    read();
    for (int i = 1; i <= n; i++) {
        if (viz[i] == 0) {
            k++;
            dfs(i);
        }
    }
    cout << k;
    return 0;
}