#include <fstream>
#include <vector>
#include <deque>
#define DIM 100010
using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

vector <int> L[DIM], sol[DIM];
deque <int> s;
int niv[DIM], low[DIM], viz[DIM];
int n,m,i,x,y,comp,j;

void dfs(int nod, int tata){
    viz[nod] = 1;
    niv[nod] = niv[tata] + 1;
    low[nod] = niv[nod];

    s.push_back(nod); /// retin nodurile in ordine
    for(int i=0;i<L[nod].size();i++){
        int vecin = L[nod][i];
        if(vecin == tata)
            continue;
        if(viz[vecin] == 1)
            low[nod] = min(low[nod],niv[vecin]);

        else {
            dfs(vecin, 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[nod]){
                /// am componenta biconexa din cauza muchiei nod-vecin
                //cout<<"a";
                comp++;
                sol[comp].push_back(nod);
                int val;
                do{
                    sol[comp].push_back(s.back());
                    val = s.back();
                    s.pop_back();
                } while (val != 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(1,0);

    fout<<comp<<"\n";
    for(i=1;i<=comp;i++){
        for(j=0;j<sol[i].size();j++)
            fout<<sol[i][j]<<" ";
        fout<<"\n";
    }

    return 0;
}