#include <iostream>
#include <vector>
using namespace std;

bool mark[100000] = {};
int dfs(int s, vector<vector<long long> >& v , vector<long long>& res) {
    int cnt = 1;
    mark[s] = 1;
    for (int i = 0 ; i < v[s].size(); ++i) {
        if (mark[v[s][i]]  != 1) {
            cnt += dfs(v[s][i], v, res);
            res.push_back(v[s][i]);
        }
    }
    return cnt;
}

int main () {
    int n, m;
    cin >> n >> m;
    vector <vector < long long > > v(n);
    vector <vector < long long > > res;

    for (int i = 0 ; i < m ; ++i) {
        int a, b;
        cin >> a >> b;
        v[a - 1].push_back(b - 1);
        v[b - 1].push_back(a - 1);
    }
    for (int i = 0; i < n; ++i) {
        if (mark[i]) continue;
        vector<long long > tmp;
        tmp.push_back(i);
        dfs(i, v, tmp);
        res.push_back(tmp);
    }

    cout << res.size() << "\n" ;
    for (int i = 0; i < res.size(); ++i) {
        cout << res[i].size() << "\n";
        for (int j = 0; j < res[i].size(); ++j) {
            cout << res[i][j] + 1 << " ";
        }
        cout << "\n";
    }
    return 0;
}