#include <iostream>
#include <fstream>
#include <vector>

using namespace std;

ifstream fin ("biconex.in");
ofstream fout ("biconex.out");

#define lim 100010
int n,m,dr;
vector <int> G[lim];
bool viz[lim];
int lvlmin[lim], lvl[lim];
vector <vector <int>> sol;
struct nodd {int x,y;} st[lim];

void dfs (int nod, int dad)
{
    viz[nod]=1;
    lvl[nod] = lvl[dad]+1;
    lvlmin[nod] = lvl[nod];

    for (auto it:G[nod])
        if (!viz[it])
        {
            st[++dr] = {nod, it};
            dfs (it, nod);
            lvlmin[nod] = min (lvlmin[nod], lvlmin[it]);
            if (lvlmin[it] >= lvl[nod])
            {
                vector <int> aux;
                while (dr && (st[dr].x!=nod && st[dr].y!=it))
                {
                    aux.push_back (st[dr].y);
                    dr--;
                }
                dr--;
                aux.push_back(nod);
                aux.push_back(it);
                sol.push_back(aux);
            }
        }
        else lvlmin[nod] = min (lvlmin[nod], lvl[it]);
}

int main()
{
    int x,y;
    fin>>n>>m;
    for (int i=1; i<=m; i++)
    {
        fin>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    for (int i=1; i<=n; i++)
        if (!viz[i])
            dfs (i, 0);

    fout<<sol.size()<<'\n';
    for (auto it:sol)
    {
        for (auto itt:it)
            fout<<itt<<' ';
        fout<<'\n';
    }

    fout.close();
    return 0;
}