# include <fstream>
# include <algorithm>
# include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
vector <int> v[100005],sol[100005];
struct elem
{
    int x, y;
}st[100005],E;
int i,j,n,m,x,y,VV,nrsol;
int ap[100005],niv[100005],minn[100005];
void DFS (int k, int nivel, int tata)
{
    int i;
    ap[k]=1; niv[k]=nivel; minn[k]=nivel;
    for (i=0; i<v[k].size(); ++i)
    {
        if (v[k][i]!=tata)
        {
            if (! ap[v[k][i]])
            {
                E.x=k; E.y=v[k][i]; st[++VV]=E;
                DFS (v[k][i],nivel+1,k);
                minn[k]=min(minn[k], minn[v[k][i]]);
                if (minn[v[k][i]]>=nivel) //trebuie sa scoatem
                {
                    sol[++nrsol].push_back(k);
                    while (st[VV].x!=k)
                    {
                        sol[nrsol].push_back(st[VV].y);
                        --VV;
                    }
                    sol[nrsol].push_back(st[VV].y);
                    --VV;
                }
            }
            else minn[k]=min(minn[k],niv[v[k][i]]);
        }
    }
}
int main ()
{
    f>>n>>m;
    for (i=1; i<=m; ++i)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    DFS (1,1,0);
    g<<nrsol<<"\n";
    for (i=1; i<=nrsol; ++i)
    {
        for (j=0; j<sol[i].size(); ++j)
            g<<sol[i][j]<<" ";
        g<<"\n";
    }
    return 0;
}