#include <algorithm>
#include <vector>
#include <stack>
using namespace std;

#define pb push_back
#define mp make_pair
#define DIM 100005
#define sc second
#define fs first

vector <int> g[DIM],cb[DIM];
stack <pair <int,int> > st;
int lvl[DIM],dfn[DIM];
int n,m,ncb;

void read ()
{
    int i,x,y;

    scanf ("%d%d",&n,&m);
    for (i=1; i<=m; ++i)
    {
        scanf ("%d%d",&x,&y);
        g[x].pb (y);
        g[y].pb (x);
    }
}

inline void insert (int nod1,int nod2)
{
    pair <int,int> nod;

    ++ncb;
    do
    {
        nod=st.top (); st.pop ();
        cb[ncb].pb (nod.fs);
        cb[ncb].pb (nod.sc);
    }
    while (nod.fs!=nod1 && nod.sc!=nod2);
}

void df (int nod,int tata,int lv)
{
    vector <int> :: iterator it;

    dfn[nod]=lvl[nod]=lv;
    for (it=g[nod].begin (); it!=g[nod].end (); ++it)
        if (*it!=tata)
            if (dfn[*it])
                lvl[nod]=min (lvl[nod],dfn[*it]);
            else
            {
                st.push (mp (nod,*it));
                df (*it,nod,lv+1);
                lvl[nod]=min (lvl[nod],lvl[*it]);
                if (lvl[*it]>=dfn[nod])
                    insert (nod,*it);
            }
}

void print ()
{
    vector <int> :: iterator it;
    int i;

    printf ("%d\n",ncb);
    for (i=1; i<=ncb; ++i)
    {
        sort (cb[i].begin (),cb[i].end ());
        cb[i].erase (unique (cb[i].begin (),cb[i].end ()),cb[i].end ());
        for (it=cb[i].begin (); it!=cb[i].end (); ++it)
            printf ("%d ",*it);
        printf ("\n");
    }
}

int main ()
{
    freopen ("biconex.in","r",stdin);
    freopen ("biconex.out","w",stdout);

    read ();
    df (1,0,1);
    print ();

    return 0;
}