#include <cstdio>
#include <cstring>
#include <fstream>
#include <vector>
#define Nmx 100002

using namespace std;

int n,m,lvl[Nmx],c[Nmx],nr,nrs,viz[Nmx];
vector <int> sol[Nmx];
struct dat
{ int x,y;}A[Nmx*3];
struct nod
{
    int inf;
    nod *urm;
};
nod *G[Nmx];


ifstream fin("biconex.in");

void add(int x,int y)
{
    nod *aux=new nod;
    aux->inf = y;
    aux->urm = G[x];
    G[x] = aux;
}

void read()
{
    int x,y;
    fin>>n>>m;
    for(int i=1;i<=m;++i)
    {
        fin>>x>>y;
        add(x,y);
        add(y,x);
    }
}

void baga(int x,int y)
{
    int px,py;
    ++nrs;
    do
    {
        px=A[nr].x;
        py=A[nr--].y;
        sol[nrs].push_back(py);
    }while(px!=x||py!=y);
    sol[nrs].push_back(x);
}

void dfs(int nd,int tata)
{
    lvl[nd]=lvl[tata]+1;
    c[nd]=lvl[nd];
    viz[nd]=1;
    for(nod *p=G[nd];p;p=p->urm)
    {
        int x=p->inf;
        if(!viz[x])
        {
            A[++nr].x=nd;
            A[nr].y=x;
            dfs(x,nd);
            if(c[x]<c[nd])
                c[nd]=c[x];
            if(c[x]>=lvl[nd])
                baga(nd,x);
        }
        else if(tata!=x&&c[x]<c[nd])
                c[nd]=c[x];
    }
}

int main()
{
    freopen("biconex.out","w",stdout);
    read();
    dfs(1,0);
    printf("%d\n",nrs);
    for(int i=1;i<=nrs;++i)
    {
        for(int j=0;j<sol[i].size();++j)
            printf("%d ",sol[i][j]);
        printf("\n");
    }
    return 0;
}