#include <iostream>
#include <vector>
using namespace std;
int N;
vector<vector<int>>g;
vector <bool>visited(false);
int ss = 0;
vector<int>color;
vector<int>klv;
vector<vector<int>>nv;
void DFS(int V)
{
    visited[V] = true;
    color[V] = ss;
    nv[ss].push_back(V);
    for (int i = 0; i < g[V].size(); i++)
    {
        int to = g[V][i];
        if (!visited[to])
        {
            DFS(to);
        }
    }
}
int main()
{
    int M, a, b,q;
    cin >> N >> M;
    g.resize(N);
    nv.resize(N);
    visited.resize(N);
    for (int i = 0; i < M; i++)
    {
        cin >> a >> b;
        a--;
        b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    color.resize(N);
    for (int i = 0; i < N; i++)
    {
        if (!visited[i])
        {
            ss++;
            DFS(i);
        }
    }
    cout << ss;
    for (int i = 1; i <= ss; i++)
    {
        cout << endl << nv[i].size() << endl;
        q = nv[i].size();
        while (q > 0)
        {
            cout << nv[i][q - 1] + 1 << " ";
            q--;
        }
    }
    return 0;
}