#include <iostream>
#include <fstream>
using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");
struct node {
    int value;
    node *next;
};
node *v[100001];
void add(node* &head, int val) {
    node* el = new node;
    el -> value = val;
    el -> next = head;
    head = el;
}
void DFS(node* &head, int visited[100001]) {
        while(head != NULL) {
            int nr = head -> value;
            if(visited[nr] == 0) {
                visited[nr] = 1;
                DFS(v[nr],visited);
            }
            head = head -> next;
        }
}
int main()
{
    int n, m, nrComp = 0, visited[100001];
    f >> n >> m;
    for(int i = 1; i <= n; i++) {
        visited[i] = 0;
        v[i] = NULL;
    }
    while(m--) {
        int x, y;
        f >> x >> y;
        add(v[x], y);
        add(v[y], x);
    }
    for(int i = 1; i <= n; i++) {
        if(visited[i] == 0) {
            visited[i] = 1;
            nrComp++;
            DFS(v[i], visited);
        }
    }
    g << nrComp;
    f.close();
    g.close();
    return 0;
}