#include <iostream>
#include <vector>
#include <algorithm>
#include <iterator>
#include <unordered_map>
#include <unordered_set>
#include <string>

class Graph {
 private:
    std::unordered_map<int, std::vector<int>> edges;
    std::unordered_set<int> used;
    std::unordered_set<int> notused;

 public:
    Graph() {
    }

    explicit Graph(int n) {
        for (int i = 0; i < n; i++) {
            edges[i + 1] = {};
            notused.insert(i + 1);
        }
    }

    std::unordered_set<int> vertexes() {
        std::unordered_set<int> res;
        for (auto i : edges) {
            res.insert(i.first);
        }
        return res;
    }

    void insert(int a, int b) {
        edges[a].push_back(b);
        edges[b].push_back(a);
        notused.insert(a);
        notused.insert(b);
    }

    void subgraph2(int a) {
        if (used.find(a) == used.end()) {
            used.insert(a);
            notused.erase(a);
            for (auto i : edges[a]) {
                subgraph2(i);
            }
        }
    }

    std::unordered_set<int> subgraph(int a) {
        used.clear();
        subgraph2(a);
        return used;
    }

    std::unordered_set<int> notuseds() {
        return notused;
    }
};

int main() {
    int N, M;
    int a, b;
    std::cin >> N >> M;
    if (N != 0 && M != 0) {
        Graph graph(N);
        for (int i = 0; i < M; i++) {
            std::cin >> a >> b;
            graph.insert(a, b);
        }
        std::unordered_set<int> vertexes;
        vertexes = graph.notuseds();
        int number = 0;
        std::vector<std::unordered_set<int>> result;
        std::unordered_set<int> preresult;
        std::unordered_set<int> difference;
        while (vertexes.size() != 0) {
            preresult = graph.subgraph(*vertexes.begin());
            result.push_back(preresult);
            vertexes = graph.notuseds();
            number++;
        }
        std::cout << number << '\n';
        for (int i = 0; i < number; i++) {
            std::cout << result[i].size() << '\n';
            std::cout << *result[i].begin();
            auto beg = result[i].begin();
            beg++;
            while (beg != result[i].end()) {
                std::cout << " " << *beg++;
            }
            std::cout << '\n';
        }
    } else if (N == 0) {
        std::cout << 0;
    } else {
        std::cout << N << '\n';
        for (int i = 0; i < N; i++) {
            std::cout << 1 << '\n' << i + 1 << '\n';
        }
    }
}