#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define SZ(v) ((int)(v).size())
#define pb push_back
const int N = 2e5+9;
const int inf = 1e9+9;

vector<int> adj[N];
bool vis[N];


void DFS (int st_node) {
    vis[st_node] = true;
    for (int neg : adj[st_node]) {
        if (!vis[neg]) {
            DFS(neg);
        }
    }
}
/*
    5 4
    1 2
    1 3
    3 4
    4 5


    1 -> 2 3
    2 -> 1
    3 -> 1 4
    4 -> 3 5
    5 -> 4
    6 ->

 */

void run () {
    int n, m;
    cin >> n >> m;
    for (int i = 0; i < m; ++i) {
        int u, v;
        cin >> u >> v;
        // undirected
        // u -> v
        // v -> u
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    DFS(1);
    int count = 1;
    for (int node = 1; node <= n; ++node) {
        if (!vis[node]) {
            count++;
            DFS(node);
        }
    }
    cout << count << '\n';
}
int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);
    freopen("/home/hamoudi/clion/hello.in", "rt", stdin);
    int tt;
    tt = 1;
    //    cin >> tt;
    while (tt--)
        run();
    return 0;
}