//Основы теории графов и dfs. Теория. Задача E.
#include <bits/stdc++.h>
using namespace std;
int n, m;
vector < vector < int > > g;
vector < bool > used;
vector < int > cur;

void dfs(int v) {
    if (used[v]) return;
    used[v] = true;
    cur.push_back(v + 1);
    for (auto u : g[v]) {
        dfs(u);
    }
}

int main() {
    cin >> n >> m;
    g.resize(n);
    used.resize(n, false);
    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        a--; b--;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    vector < vector < int > > ans;
    for(int i = 0; i < n; i++) {
        if (!used[i]) {
            cur.clear();
            dfs(i);
            ans.push_back(cur);
        }
    }
    cout << ans.size() << endl;
    for (auto &e : ans) {
        sort(e.begin(), e.end());
        cout << e.size() << endl;
        for (auto v : e) {
            cout << v << " ";
        }
        cout << endl;
    }
    return 0;
}