#include<fstream>
#include<vector>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,NIV[100001],ORD[100001],poz=1,X[100001],k;
vector<int> V[100001];//listele de adiacenta
int ns;
vector<int> S[100001];//solutia

int DF(int v,int niv)
{
    if(NIV[v])
        return NIV[v];//nivelul pe care e deja pus
    int minlvl=niv,minn,niv2;
    NIV[v] = niv;//pun nivelul
    ORD[v] = poz++;//ordinea in care sunt parcurse in df
    X[++k] = v;//adaug v in parcurgere
    for(int i = 0;i < V[v].size(); ++i)
    {
        niv2 = poz;
        minn = DF(V[v][i],niv+1);//parcurge incepand cu nodul adiacent
        if(minn>=niv)//exista muchie de intoarcere
        {
            ns++;//maresc nr solutii
            while(ORD[X[k]]>=niv2)//iau vb din vectorul parcurgerii df
            {
                S[ns].push_back(X[k]);//adaug varfurle in componenta biconexa
                k--;                //din parcurgerea df
            }
            if(S[ns].size())
                S[ns].push_back(v);//adaug si nodul initial
            else//daca nu s-a adaugat nimic
                ns--;

        }
        if(minn<minlvl)
            minlvl = minn;
    }
    return minlvl;//returneaza nivelul minim de intoarcere
}

int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        fin>>x>>y;
        V[x].push_back(y);
        V[y].push_back(x);
    }
    for(int i=1;i<=n;++i)
        if(!NIV[i])
            DF(i,1);
    fout<<ns<<endl;
    for(int i=1;i<=ns;++i)
    {
        for(int j=0;j<S[i].size();++j)
            fout<<S[i][j]<<" ";
        fout<<endl;
    }
    fin.close();
    fout.close();
    return 0;
}