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

using namespace std;

const int MAXN = 100001;

vector<int> adj[MAXN];
int discoveryTime[MAXN], low[MAXN], visited[MAXN];
int timer = 0;
stack<pair<int, int>> edgeStack;
vector<vector<int>> biconnectedComponents;

void dfs(int u, int parent) {
    visited[u] = 1;
    discoveryTime[u] = low[u] = ++timer;
    int children = 0;

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

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


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

void findBiconnectedComponents(int n) {
    for (int i = 1; i <= n; i++) {
        if (!visited[i]) {
            dfs(i, -1);
            
            if (!edgeStack.empty()) {
                vector<int> component;
                while (!edgeStack.empty()) {
                    auto edge = edgeStack.top();
                    edgeStack.pop();
                    component.push_back(edge.first);
                    component.push_back(edge.second);
                }
                sort(component.begin(), component.end());
                component.erase(unique(component.begin(), component.end()), component.end());
                biconnectedComponents.push_back(component);
            }
        }
    }
}

int main() {
    ifstream fin("biconex.in");
    ofstream fout("biconex.out");

    int N, M;
    fin >> N >> M;

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

    findBiconnectedComponents(N);

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

 

    return 0;
}