#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
#define MAX 100010
#define cout fout
typedef vector <int> :: iterator iter;
vector <int> G[MAX], ans;
vector <vector <int> > rez;

int viz[MAX], lvl[MAX], down[MAX], dr;
pair<int, int> st[MAX];

void df(int nod, int dad)
{
    viz[nod] = 1;
    lvl[nod] = lvl[dad] + 1;
    down[nod] = lvl[nod];
    for(iter it = G[nod].begin() ; it != G[nod].end() ; it++)
    {
        if(*it == dad)
            continue;
        if(viz[*it])
        {
            down[nod] = min(down[*it], down[nod]);
        }
        else
        {
            st[++dr] = make_pair(nod, *it);
            df(*it, nod);
            if(down[*it] >= lvl[nod])
            {
                ans.clear();
                while(st[dr].first != nod)
                {
                    ans.push_back(st[dr].second);
                    dr--;
                }
                ans.push_back(st[dr].second);
                ans.push_back(st[dr].first);
                dr--;
                rez.push_back(ans);
            }
            down[nod] = min(down[nod], down[*it]);
        }
    }
}


int main()
{
    int n, m, x, y;
    fin >> n >> m;
    while(m--)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    df(1, 0);
    cout << rez.size() << "\n";
    for(int i = 0 ; i < rez.size() ; i++)
    {
        for(iter it = rez[i].begin() ; it != rez[i].end() ; it++)
            cout << *it << " ";
        cout << "\n";
    }
}