#include <iostream>
#include <fstream>
using namespace std;
ifstream in("dfs.in");
ofstream out("dfs.out");

int n, m, vizited[100001], ans;

typedef struct nod {
        int x;
        nod *a;
} *dNod;
dNod v[100001];

void adaugare(dNod &q, int val) {
        dNod p;
        p = new nod;
        p -> x = val;
        p -> a = q;
        q = p;
}

void citire() {
    in >> n >> m;
    int x, y;

    for (int i = 1; i <= m; ++i) {
        in >> x >> y;

        adaugare(v[x], y);
        adaugare(v[y], x);
    }
}

void DFS(int nod) {
        dNod p;
        vizited[nod] = 1;

        for (p = v[nod]; p != 0; p = p -> a)
            if (!vizited[p -> x])
               DFS(p -> x);
}

int main() {
    citire();

    for (int i = 1; i <= n; ++i)
        if (!vizited[i]) {
           ++ans;
           DFS(i);
        }

    out << ans;
    return 0;
}