#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,i,x,y;
vector <int> vec[100005];
vector <int> sol,stiv;
struct per{int x,y;}aux;
vector <per> muc;
vector <int> comp[100005];
int nrcomp;
int niv[100005],nma[100005],nr1;
void dfs(int x)
{
    nma[x]=niv[x];
    stiv.push_back(x);
    for(int i:vec[x])
    {
        if(niv[i]==0)
        {
            if(x==1)
                nr1++;
            niv[i]=niv[x]+1;
            dfs(i);
            nma[x]=min(nma[x],nma[i]);
            if(niv[x]<=nma[i]&&x!=1)
            {
                sol.push_back(x);
            }
            if(niv[x]<=nma[i])
            {
                nrcomp++;
                while(stiv.back()!=i)
                {
                    comp[nrcomp].push_back(stiv.back());
                    stiv.pop_back();
                }
                comp[nrcomp].push_back(stiv.back());
                    stiv.pop_back();
                comp[nrcomp].push_back(x);
            }
            if(niv[x]<nma[i])
            {
                aux.x=x;
                aux.y=i;
                muc.push_back(aux);
            }
        }
        else
            if(niv[x]!=niv[i]+1)
            nma[x]=min(nma[x],niv[i]);
    }
}
void afisArticulatii()
{
    fout<<sol.size()<<'\n';
    while(!sol.empty())
    {
        fout<<sol.back()<<'\n';
        sol.pop_back();
    }
}
void afisPunti()
{
    fout<<muc.size()<<'\n';
    while(!muc.empty())///afisare muchiii
    {
        fout<<muc.back().x<<" "<<muc.back().y<<'\n';
        muc.pop_back();
    }
}
void afisComponente()
{
    fout<<nrcomp<<'\n';
    for(i=1;i<=nrcomp;i++)
    {
        sort(comp[i].begin(),comp[i].end());
        for(int z:comp[i])
        {
            fout<<z<<" ";
        }
        fout<<'\n';
    }
}
int main()
{
    fin>>n>>m;
    for(i=1;i<=m;i++)
    {
        fin>>x>>y;
        vec[x].push_back(y);
        vec[y].push_back(x);
    }
    niv[1]=1;
    dfs(1);
    if(nr1>1)
        sol.push_back(1);
    afisComponente();



    return 0;
}