#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;
};
muchie st[mmax];
int n, m, dfn[nmax], low[nmax], c=0, num=0, start=1, vf=0;
vector<int> g[nmax], sol[nmax];
void citire()
{
    int i, x, y;
    fin>>n>>m;
    for(i=0; i<m; i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    fin.close();
}
void componenta(int x, int u)
{
    muchie p;
    bool used[nmax]={0};
    c++;
    do
    {
        p=st[vf];
        vf--;
        if(!used[p.t])
            sol[c].push_back(p.t);
        if(!used[p.f])
            sol[c].push_back(p.f);
        used[p.f]=used[p.t]=1;
    }while(p.t!=u || p.f!=x);
}
void dfs(int u, int tu)
{
    vector<int>::iterator it;
    num++;
    low[u]=dfn[u]=num;
    for(it=g[u].begin(); it!=g[u].end(); it++)
    {
        if(*it!=tu && dfn[*it]<dfn[u])
        {
            vf++;
            st[vf].f=*it; st[vf].t=u;
        }
        if(dfn[*it]==-1)
        {
            dfs(*it, u);
            low[u]=min(low[u], low[*it]);
            if(low[*it]>=dfn[u])
                componenta(*it, u);
        }
        else if(*it!=tu)
            low[u]=min(low[u], dfn[*it]);
    }
}
void initializare()
{
    int i;
    for(i=1; i<=n; i++)
        low[i]=dfn[i]=-1;
    st[0].f=1; st[0].t=-1;
}
void afisare()
{
    int i;
    vector<int>::iterator it;
    fout<<c<<'\n';
    for(i=1; i<=c; i++)
    {
        for(it=sol[i].begin(); it!=sol[i].end(); it++)
            fout<<*it<<' ';
        fout<<'\n';
    }
    fout.close();
}
int main()
{
    citire();
    initializare();
    dfs(start, -1);
    afisare();
    return 0;
}