# include <fstream>
# include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
vector <int> v[100005];
vector <int> sol[100005];
struct elem
{
    int x,y;
}stiva[100005],var;
int low[100005]; //nivelul minim in care poate ajunge un elem din arborele unui element
int fii[100005],niv[100005],ap[100005];
int i,j,n,m,x,y,ok,VV,nrsol,st;
void DFS(int k, int nivel, int parinte)
{
    ap[k]=1; niv[k]=nivel; low[k]=nivel;
    for (int i=0; i<v[k].size(); ++i)
    {
        int ok=0;
        if (v[k][i]!=parinte)
        {
            if (ap[v[k][i]]==0)
            {
                var.x=k; var.y=v[k][i];
                stiva[++st]=var;
                ++fii[k]; ok=1;
                DFS(v[k][i], nivel+1, k);
            }
            low[k]=min(low[k], low[v[k][i]]);
            if (low[v[k][i]]>=nivel && ok)
            {
                ++VV; ++nrsol;
                sol[nrsol].push_back(k);
                int nr=0;
                while (stiva[st].x!=k)
                {
                    sol[nrsol].push_back(stiva[st].y);
                    --st;
                }
                sol[nrsol].push_back(stiva[st].y);
                --st;
            }
        }
    }
}
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<<VV<<"\n";
    for (i=1; i<=nrsol; ++i)
    {
        for (j=0; j<sol[i].size(); ++j)
            g<<sol[i][j]<<" ";
        g<<"\n";
    }
    return 0;
}