B_11724

import java.util.*;
import java.io.*;

public class main {
    static ArrayList<Integer>[] arr;
    static boolean[] c;
    static boolean[] ac;
    static int N,M;
    static int ans = 0;
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String s = br.readLine();
        N = Integer.parseInt(s.split(" ")[0]);
        M = Integer.parseInt(s.split(" ")[1]);

        arr = new ArrayList[N + 1];
        c = new boolean[N + 1];
        ac = new boolean[N + 1];
        for (int i = 1; i < N + 1; i++) {
            arr[i] = new ArrayList();
        }
        for (int i = 0; i < M; i++) {
            String s1 = br.readLine();
            int u = Integer.parseInt(s1.split(" ")[0]);
            int v = Integer.parseInt(s1.split(" ")[1]);
            arr[u].add(v);
            arr[v].add(u);
        }
        for (int i = 1; i < N + 1; i++) {
            if(ac[i]) continue;
            c = new boolean[N + 1];
            dfs(i);
            ans++;
        }
        System.out.println(ans);

    }


    public static void dfs(int start) {
        c[start] = true;
        ac[start] = true;

        for (int v : arr[start]) {

            if (c[v]) continue;
            dfs(v);
        }

    }
}