t111540

import java.util.ArrayList;
import java.util.Scanner;

public class Main {
    static Scanner in = new Scanner(System.in);
    static int n = in.nextInt();
    static int m = in.nextInt();
    static int[] used = new int[n + 1];
    static int k = 0;
    static ArrayList<Integer>[] array;
    static ArrayList<Integer>[] ans;

    public static void dfs(int v, int t) {
        used[v] = 1;
        ans[t].add(v);
        for (int i = 0; i < array[v].size(); i++) {
            int u = array[v].get(i);
            if (used[u] == 0) {
                dfs(u, t);
            }
        }
    }


    public static void main(String[] args) {
        array = new ArrayList[n + 1];
        ans = new ArrayList[n + 1];
        for (int i = 0; i < array.length; i++) {
            array[i] = new ArrayList<Integer>();
        }
        for (int i = 0; i < m; i++) {
            int r = in.nextInt();
            int r2 = in.nextInt();
            array[r].add(r2);
            array[r2].add(r);
        }
        for (int i = 1; i < n + 1; i++) {
            if (used[i] == 0) {
                ans[k] = new ArrayList<Integer>();
                dfs(i, k++);
            }
        }
        System.out.println(k);

        for (int i = 0; i < k; i++) {
            System.out.println(ans[i].size());
            for (int j = 0; j < ans[i].size(); j++) {
                System.out.print(ans[i].get(j) + " ");
            }
            System.out.println();
        }
    }
}