#include <fstream>
#include <vector>
#define maxn 100001
#define maxm 200001

using namespace std;

int n,m,k,poz;
bool viz[maxn];
vector <int> muchii[maxn],sol[maxn];
int nivelmin[maxn],nivel[maxn];
struct muchie
{
int a,b;
}leg[maxm];

void df(int nod,int tata)
{
 int aux,i;
 viz[nod]=1;
 nivelmin[nod]=nivel[tata]+1;
 nivel[nod]=nivel[tata]+1;
 for(i=0;i<muchii[nod].size();i++)
     {
        aux=muchii[nod][i];
        if(!viz[aux])
            {
                poz++;
                leg[poz].a=nod;
                leg[poz].b=aux;
                df(aux,nod);
                if(nivel[nod]<=nivelmin[aux])
                    {
                        k++;
                        while(leg[poz].a!=nod && leg[poz].b!=aux)
                            {
                                sol[k].push_back(leg[poz].b);
                                poz--;
                            }
                        sol[k].push_back(leg[poz].b);
                        sol[k].push_back(leg[poz].a);
                        poz--;
                    }
                nivelmin[nod]=min(nivelmin[nod],nivelmin[aux]);

            }
            else
                    if(aux!=tata)
                    if(nivelmin[nod]>nivel[aux])
                        nivelmin[nod]=nivel[aux];

        }
}
int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
scanf("%d%d",&n,&m);
for(int j=0;j<=m;++j)
{
int x,y;
scanf("%d%d",&x,&y);
muchii[x].push_back(y);
muchii[y].push_back(x);
}

for(int i=1;i<=n;i++)
if(!viz[i]) df(i,.1);
printf("%d\n",k);
for(int i=1;i<=n;i++)
{
for(int j=sol[i].size()-1;j>=0;j--)
printf("%d ",sol[i][j]);
printf("\n");
}
return 0;
}