#include <fstream>
#include <vector>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
#define nmax 100005
#define mmax 200005
struct muchie
{
    int f, t;
};
int n, m, dfn[nmax], low[nmax], num=0, nrcm=0, vfst=0;
bool used[nmax]={0};
vector<int> g[nmax], sol[nmax];
muchie st[mmax];
void citire()
{
    int i, x, y;
    fin>>n>>m;
    for(i=1; i<=m; i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    fin.close();
}
void initializare()
{
    int i;
    for(i=1; i<=n; i++)
        low[i]=dfn[i]=-1;
}
void componenta(int f, int t)
{
    muchie p;
    vector<int>::iterator it;
    do
    {
        p=st[vfst--];
        if(!used[p.f])
        {
            used[p.f]=1;
            sol[nrcm].push_back(p.f);
        }
        if(!used[p.t])
        {
            used[p.t]=1;
            sol[nrcm].push_back(p.t);
        }
    }while((p.t!=t || p.f!=f) && vfst>0);
    for(it=sol[nrcm].begin(); it!=sol[nrcm].end(); it++)
        used[*it]=0;
    nrcm++;
}
void dfs(int nod, int tata)
{
    vector<int>::iterator it;
    num++;
    low[nod]=dfn[nod]=num;
    for(it=g[nod].begin(); it!=g[nod].end(); it++)
    {
        if(*it!=tata && dfn[*it]<dfn[nod])
        {
            vfst++;
            st[vfst].f=*it; st[vfst].t=nod;
        }
        if(dfn[*it]==-1)
        {
            dfs(*it, nod);
            low[nod]=min(low[nod], low[*it]);
            if(low[*it]>=dfn[nod])
                componenta(*it, nod);
        }
        else if(*it!=tata)
            low[nod]=min(low[nod], dfn[*it]);
    }
}
void afisare()
{
    vector<int>::iterator it;
    int i;
    fout<<nrcm<<'\n';
    for(i=0; i<nrcm; i++)
    {
        for(it=sol[i].begin(); it!=sol[i].end(); it++)
            fout<<*it<<' ';
        fout<<'\n';
    }
    fout.close();
}
int main()
{
    citire();
    initializare();
    dfs(1, -1);
    afisare();
    return 0;
}