# include <fstream>
# include <algorithm>
# include <vector>
# define NR 200005
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
vector <int> v[NR], sol[NR];
struct elem {
    int x, y;
}st[NR];
int i,j,n,m,x,y,VV,nrsol;
int niv[NR], T[NR], minn[NR], ap[NR];

void DFS (int k, int nivel, int tata) {
    ap[k]=1; niv[k]=nivel; T[k]=tata; minn[k]=nivel;
    for (int i=0; i<v[k].size(); ++i) {
        int urm=v[k][i];
        if (urm!=tata) {
            if (! ap[urm]) {
                 st[++VV].x=k; st[VV].y=urm;
                 DFS (urm, nivel+1, k);

                 if (minn[urm] >= nivel) {
                    ++nrsol;
                    sol[nrsol].push_back(k);

                    while (st[VV].x != k) {
                        sol[nrsol].push_back(st[VV].y);
                        --VV;
                    }

                    sol[nrsol].push_back(urm);
                    --VV;
                 }
                minn[k]=min(minn[k], minn[urm]);
            }
            else minn[k]=min(minn[k], niv[urm]);
        }
    }
}
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;
}