import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.*;

public class Main {
    private static final String INPUT_FILE_PATH = "dfs.in";
    private static final String OUTPUT_FILE_PATH = "dfs.out";

    public static void main(String[] args) throws IOException {
        Scanner in = new Scanner(new FileReader(INPUT_FILE_PATH));
        PrintWriter out = new PrintWriter(OUTPUT_FILE_PATH);
        int n = in.nextInt();
        int m = in.nextInt();
        UndirectedGraph mGraph = new UndirectedGraph(n);
        while (m-- > 0) {
            int source = in.nextInt();
            int dest = in.nextInt();
            mGraph.addEdge(source, dest);
        }
        int c = mGraph.countConnectedComponents();
        out.print(c);
        out.flush();
        in.close();
        out.close();
    }

    static class UndirectedGraph {
        private Map<Integer, List<Integer>> adjList = new HashMap<>();
        private int cntNodes;

        public UndirectedGraph(int n) {
            this.cntNodes = n;
        }

        public void addEdge(int x, int y) {
            this.adjList.computeIfAbsent(x, k -> new ArrayList<>()).add(y);
            this.adjList.computeIfAbsent(y, k -> new ArrayList<>()).add(x);
        }

        public int countConnectedComponents() {
            boolean[] visited = new boolean[cntNodes + 1];
            int cnt = 0;
            for (int i = 1; i <= cntNodes; ++i) {
                if (!visited[i]) {
                    ++cnt;
                    dfs(i, visited);
                }
            }
            return cnt;
        }

        private void dfs(int node, boolean[] visited) {
            visited[node] = true;
            List<Integer> relatedNodes = this.adjList.get(node);
            if (relatedNodes == null) {
                return;
            }
            for (int rNode : relatedNodes) {
                if (!visited[rNode]) {
                    dfs(rNode, visited);
                }
            }
        }
    }
}