#include <bits/stdc++.h>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
struct noduri{vector <int> v;int d;int dmin;bool pda;}v[100003];///pda=punct de articulatie
int n,m;
bool tr[100003];
bool pda1=0;
stack <int> st;
struct componente{vector <int> c;}aux;
vector <componente> cmp;
//vector <int> vgol;
void dfs(int nod,int tata)
{
    st.push(nod);
    tr[nod]=1;
    v[nod].d=v[tata].d+1;
    v[nod].dmin=v[nod].d;
    for(int i=0;i<v[nod].v.size();i++)
    {
        int newnode=v[nod].v[i];
        if(newnode!=tata)
        {
            if(tr[newnode]==0)///e muchie din arbore adica e descendent direct
            {
                dfs(newnode,nod);
                v[nod].dmin=min(v[nod].dmin,v[newnode].dmin);
                if(v[nod].d<v[newnode].dmin);///e muchie critica
                if(v[nod].d<=v[newnode].dmin)///totul din stack pana la newnode e o comp biconexa
                {
                    cmp.push_back(aux);
                    while(st.top()!=newnode)
                    {
                        cmp[cmp.size()-1].c.push_back(st.top());
                        st.pop();
                    }
                    cmp[cmp.size()-1].c.push_back(st.top());
                    st.pop();
                    cmp[cmp.size()-1].c.push_back(nod);
                }
            }
            else///e muchie de intoarcere
            {
                v[nod].dmin=min(v[nod].dmin,v[newnode].d);
            }
            if(v[nod].d<=v[newnode].dmin && nod!=1)v[nod].pda=1;
        }

    }
    if(tata==1)///are fiu
    {
        if(pda1==0)pda1=1;
        else v[1].pda=1;
    }
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        f>>x>>y;
        v[x].v.push_back(y);
        v[y].v.push_back(x);
    }
    v[1].d=1;v[1].dmin=1;
    dfs(1,0);
    g<<cmp.size()<<'\n';;
    for(int i=0;i<cmp.size();i++){
        for(int j=0;j<cmp[i].c.size();j++)
            g<<cmp[i].c[j]<<" ";g<<'\n';}
}