#include <bits/stdc++.h>

std::ifstream fin("biconex.in");
std::ofstream fout("biconex.out");

const int MOD = 1e9 + 7;
const int INF = 1e9 + 5;
const int64_t LONG_INF = static_cast<int64_t>(1e18) + 5;

const int NMAX = 1e5 + 5;

int n, m;
std::vector<int> graph[NMAX];
std::vector<int> biconex_comp[NMAX];
int lvl[NMAX], min_lvl[NMAX], biconex_cnt;

void dfs(int node, int parent, std::stack<int> &st) {
    lvl[node] = min_lvl[node] = lvl[parent] + 1;
    st.push(node);
    for (auto adj : graph[node]) {
        if (adj == parent) {
            continue;
        }

        // found back-edge
        if (lvl[adj]) {
            min_lvl[node] = std::min(min_lvl[node], lvl[adj]);
            continue;
        }

        dfs(adj, node, st);
        min_lvl[node] = std::min(min_lvl[node], min_lvl[adj]);
        // found articulation point
        if (lvl[node] <= min_lvl[adj]) {
            // get biconex component
            biconex_cnt++;
            biconex_comp[biconex_cnt].push_back(node);
            int comp_node;
            do {
                comp_node = st.top();
                biconex_comp[biconex_cnt].push_back(comp_node);
                st.pop();
            } while (comp_node != adj);
        }
    }
}

int main() {
    std::ios_base::sync_with_stdio(false);
    std::cin.tie(nullptr);

    fin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        int x, y;
        fin >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }

    std::stack<int> st;
    for (int i = 1; i <= n; ++i) {
        if (!lvl[i]) {
            dfs(i, 0, st);
        }
    }

    fout << biconex_cnt << "\n";
    for (int i = 1; i <= biconex_cnt; ++i) {
        for (auto node : biconex_comp[i]) {
            fout << node << " ";
        }
        fout << "\n";
    }

    return 0;
}