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

int dfs(std::vector<std::vector<int>>& adj, std::vector<bool>& visited, std::vector<int>& lvl, std::stack<int>& st, std::vector<std::vector<int>>& sol, int& nrSol, int node, int parentNode) {
    if(visited[node]) return lvl[node];
    visited[node] = true;
    lvl[node] = lvl[parentNode] + 1;
    int minLvl = lvl[node];
    st.push(node);
    for(int i = 0; i < adj[node].size(); i++) {
        bool isVisited = visited[adj[node][i]];
        if(adj[node][i] != parentNode) {
            int tmp = dfs(adj, visited, lvl, st, sol, nrSol, adj[node][i], node);
            if(!isVisited && tmp >= lvl[node]) {
                while(st.top() != adj[node][i]) {
                    sol[nrSol].push_back(st.top());
                    st.pop();
                }
                sol[nrSol].push_back(st.top());
                sol[nrSol].push_back(node);
                st.pop();
                nrSol++;
            }
            minLvl = std::min(minLvl, tmp);
        }
    }
    return minLvl;
}

void biconex(std::vector<std::vector<int>>& adj, std::vector<bool>& visited, std::vector<int>& lvl, std::stack<int>& st, std::vector<std::vector<int>>& sol, int& nrSol, int n) {
    for(int i = 0; i < n; i++) {
        if(!visited[i])
            dfs(adj, visited, lvl, st, sol, nrSol, i, 0);
    }
}

int main() {
    std::ifstream fin("biconex.in");
    std::ofstream fout("biconex.out");
    
    int n, m, nrSol = 0;
    fin >> n >> m;
    std::vector<std::vector<int>> adj(n+1);
    for(int i = 1; i <= m; i++) {
        int u, v;
        fin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    std::vector<bool> visited(n+1, false);
    std::vector<std::vector<int>> sol(n+1);
    std::vector<int> lvl(n+1);
    lvl[0] = -1;
    std::stack<int> st;
    biconex(adj, visited, lvl, st, sol, nrSol, n);
    fout << nrSol << std::endl;
    for(int i = 0; i < nrSol; i++) {
        for(int j = 0; j < sol[i].size(); j++) {
            fout << sol[i][j] << " ";
        }
        fout << std::endl;
    }
    fin.close();
    fout.close();
}