#include <iostream>
#include <vector>
#include <stack>
#include <algorithm>
#include <fstream>

using namespace std;

const int MAXN = 100000;

vector<int> adj[MAXN];
int disc[MAXN], low[MAXN], parent[MAXN];
bool visited[MAXN];
stack<pair<int, int>> st;
vector<vector<int>> biconnectedComponents;
int timeCount = 0;

void dfs(int u) {
    static int time = 0;
    disc[u] = low[u] = ++time;
    visited[u] = true;
    int children = 0;

    for (int v : adj[u]) {
        if (!visited[v]) {
            children++;
            parent[v] = u;
            st.push({u, v});
            dfs(v);

            low[u] = min(low[u], low[v]);

            if ((parent[u] == -1 && children > 1) || (parent[u] != -1 && low[v] >= disc[u])) {
                vector<int> component;
                while (st.top().first != u || st.top().second != v) {
                    component.push_back(st.top().first);
                    component.push_back(st.top().second);
                    st.pop();
                }
                component.push_back(st.top().first);
                component.push_back(st.top().second);
                st.pop();
                sort(component.begin(), component.end());
                component.erase(unique(component.begin(), component.end()), component.end());
                biconnectedComponents.push_back(component);
            }
        } else if (v != parent[u] && disc[v] < disc[u]) {
            low[u] = min(low[u], disc[v]);
            st.push({u, v});
        }
    }
}

void findBiconnectedComponents(int n) {
    fill(disc, disc + n, -1);
    fill(low, low + n, -1);
    fill(parent, parent + n, -1);
    fill(visited, visited + n, false);

    for (int i = 0; i < n; i++) {
        if (!visited[i]) {
            dfs(i);
        }
    }

    while (!st.empty()) {
        vector<int> component;
        component.push_back(st.top().first);
        component.push_back(st.top().second);
        st.pop();
        while (!st.empty() && (component.back() == st.top().first || component.back() == st.top().second)) {
            component.push_back(st.top().first);
            component.push_back(st.top().second);
            st.pop();
        }
        sort(component.begin(), component.end());
        component.erase(unique(component.begin(), component.end()), component.end());
        biconnectedComponents.push_back(component);
    }
}

int main() {
    ifstream infile("biconex.in");
    ofstream outfile("biconex.out");

    int N, M;
    infile >> N >> M;

    for (int i = 0; i < M; ++i) {
        int x, y;
        infile >> x >> y;
        adj[x - 1].push_back(y - 1);
        adj[y - 1].push_back(x - 1);
    }

    findBiconnectedComponents(N);

    outfile << biconnectedComponents.size() << endl;
    for (const auto &component : biconnectedComponents) {
        for (int node : component) {
            outfile << node + 1 << " ";
        }
        outfile << endl;
    }

    infile.close();
    outfile.close();

    return 0;
}