#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

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

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 baga (int nod1,int nod2)
{
    vector <int> cbnr;
    int x,y;

    do
    {
        x=st.top ().fs;
        y=st.top ().sc;
        st.pop ();
        cbnr.pb (x);
        cbnr.pb (y);
    }
    while (x!=nod1 || y!=nod2);
    cb.pb (cbnr);
}

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

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

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

    memset (dfn,-1,sizeof (dfn));
    df (1,0,0);
    printf ("%u\n",cb.size ());
    for (i=0; i<(int)cb.size (); ++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 ();
    solve ();

    return 0;
}