#include <bits/stdc++.h>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");

const int NMAX = 1e5 + 5;
vector<int> graph[NMAX];
int N,M;
int timp[NMAX];
int low[NMAX];
bool viz[NMAX];
int t;
stack<int> st;
vector<vector<int> > components;
void dfs(int node,int parent){
    timp[node] = low[node] = ++t;
    viz[node] = true;
    st.push(node);
    for(auto vec:graph[node]){
        if(!viz[vec]){
            dfs(vec,node);
            low[node] = min(low[node],low[vec]);
            if(low[vec] >= timp[node]){
                vector<int> componenta;
                while(st.top()!=vec){
                    componenta.push_back(st.top());
                    st.pop();
                }
                componenta.push_back(vec);
                st.pop();
                componenta.push_back(node);
                components.push_back(componenta);
            }
        }
        else{
            if(vec != parent){
                low[node] = min(low[node],timp[vec]);
            }
        }
    }


}
int main(){
    
    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);
    }
    dfs(1,0);
    fout<<components.size()<<'\n';
    for(auto it:components){
        for(auto it2: it){
            fout<<it2<<" ";
        }
        fout<<'\n';
    }



}