import org.example.Bfs;

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

public class Main {
    static class Reader {
        final private int BUFFER_SIZE = 1 << 16;
        private DataInputStream din;
        private byte[] buffer;
        private int bufferPointer, bytesRead;

        public Reader()
        {
            din = new DataInputStream(System.in);
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public Reader(String file_name) throws IOException
        {
            din = new DataInputStream(
                    new FileInputStream(file_name));
            buffer = new byte[BUFFER_SIZE];
            bufferPointer = bytesRead = 0;
        }

        public String readLine() throws IOException
        {
            byte[] buf = new byte[64]; // line length
            int cnt = 0, c;
            while ((c = read()) != -1) {
                if (c == '\n') {
                    if (cnt != 0) {
                        break;
                    }
                    else {
                        continue;
                    }
                }
                buf[cnt++] = (byte)c;
            }
            return new String(buf, 0, cnt);
        }

        public int nextInt() throws IOException
        {
            int ret = 0;
            byte c = read();
            while (c <= ' ') {
                c = read();
            }
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');

            if (neg)
                return -ret;
            return ret;
        }

        public long nextLong() throws IOException
        {
            long ret = 0;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();
            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');
            if (neg)
                return -ret;
            return ret;
        }

        public double nextDouble() throws IOException
        {
            double ret = 0, div = 1;
            byte c = read();
            while (c <= ' ')
                c = read();
            boolean neg = (c == '-');
            if (neg)
                c = read();

            do {
                ret = ret * 10 + c - '0';
            } while ((c = read()) >= '0' && c <= '9');

            if (c == '.') {
                while ((c = read()) >= '0' && c <= '9') {
                    ret += (c - '0') / (div *= 10);
                }
            }

            if (neg)
                return -ret;
            return ret;
        }

        private void fillBuffer() throws IOException
        {
            bytesRead = din.read(buffer, bufferPointer = 0,
                    BUFFER_SIZE);
            if (bytesRead == -1)
                buffer[0] = -1;
        }

        private byte read() throws IOException
        {
            if (bufferPointer == bytesRead)
                fillBuffer();
            return buffer[bufferPointer++];
        }

        public void close() throws IOException
        {
            if (din == null)
                return;
            din.close();
        }
    }

    public static void main(String[] args) throws IOException {
        Reader scanner = new Reader("dfs.in");
        int n = scanner.nextInt();
        int m = scanner.nextInt();
        Map<Integer, List<Integer>> graph = new HashMap<>();
        for (int i = 0; i < m; i++) {
            int from = scanner.nextInt();
            int to = scanner.nextInt();
            if (!graph.containsKey(from)) {
                graph.put(from, new ArrayList<>());
            }
            graph.get(from).add(to);
            if (!graph.containsKey(to)) {
                graph.put(to, new ArrayList<>());
            }
            graph.get(to).add(from);
        }
        boolean[] visited = new boolean[n+1];
        int res = 0;
        for (int i = 1; i <= n; i++) {
            if (!visited[i]) {
                res++;
                dfs(graph, visited, i);
            }
        }
        FileWriter fileWriter = new FileWriter("dfs.out");
        PrintWriter printWriter = new PrintWriter(fileWriter);
        printWriter.write("" + res);
        printWriter.close();
    }

    private static void dfs(Map<Integer, List<Integer>> graph, boolean[] visited, int curr) {
        visited[curr] = true;
        for (var next : graph.getOrDefault(curr, List.of())) {
            if (!visited[next]) {
                dfs(graph, visited, next);
            }
        }
    }
}