import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = Files.newBufferedReader(Paths.get("dfs.in"));
        PrintWriter writer = new PrintWriter("dfs.out");

        StringTokenizer st = new StringTokenizer(br.readLine());

        int n = Integer.parseInt(st.nextToken());
        int m = Integer.parseInt(st.nextToken());

        ArrayList<Integer>[] connections = new ArrayList[n + 1];
        for (int i = 1; i < n + 1; i++) {
            connections[i] = new ArrayList<>();
        }

        for (int i = 0; i < m; i++) {
            st = new StringTokenizer(br.readLine());

            int x = Integer.parseInt(st.nextToken());
            int y = Integer.parseInt(st.nextToken());
            connections[x].add(y);
            connections[y].add(x);
        }

        int counter = 0;
        boolean[] visited = new boolean[n + 1];
        for (int i = 1; i < n + 1; i++) {
            if(visited[i]) {
               continue;
            }

            dfs(connections, i, visited);
            counter++;
        }

        writer.println(counter);

        br.close();
        writer.close();
    }

    static void dfs(ArrayList<Integer>[] connections, int node, boolean[] visited) {
        visited[node] = true;

        for(int neighbor : connections[node]) {
            if(!visited[neighbor]) {
                dfs(connections, neighbor, visited);
            }
        }
    }
}