#include <fstream>
#include <vector>
#include <stack>
#include <bitset>
#define DIM 100001
using namespace std;

ifstream fin ("biconex.in");
ofstream fout ("biconex.out");
vector <int> L[DIM];
vector <int> sol[DIM];
stack < pair<int,int> > s;
pair <int,int> mch;
bitset <DIM> viz;
int low[DIM];
int n,m,i,x,y,comp;
void dfs (int nod, int niv, int tata){
    viz[nod] = 1;
    low[nod] = niv;
    for (int i=0;i<L[nod].size();i++){
        int vecin = L[nod][i];
        if (vecin == tata)
            continue;
        if (!viz[vecin]){
            s.push(make_pair(nod,vecin)); /// retin muchiile in ordinea parcurgerii
            dfs (vecin,niv+1,nod);
            low[nod] = min (low[nod],low[vecin]);
            /// daca am cel putin un fiu din care nu pot ajunge la un stramos al lui nod
            /// ins ca nod e punct de articulatie
            if (low[vecin] >= niv){
                /// am componenta biconexa din cauza muchiei nod-vecin
                comp++;
                do{
                    mch = s.top();
                    s.pop();
                    //sol[comp].insert(mch.first);
                    sol[comp].push_back(mch.second);
                } while (mch.first != nod || mch.second != vecin);
                sol[comp].push_back(nod);
            }
        } else low[nod] = min (low[nod],low[vecin]);
    }}
int main (){

    fin>>n>>m;
    for (i=1;i<=m;i++){
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    for (i=1;i<=n;i++)
        if (!viz[i])
            dfs (i,0,0);

    fout<<comp<<"\n";
    for (i=1;i<=comp;i++){
        for (auto nod:sol[i])
            fout<<nod<<" ";
        fout<<"\n";
    }

    return 0;
}