#include <iostream>
#include <fstream>
#include <vector>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
#define MAX 100010
vector <vector <int> > comp;
typedef vector <int> :: iterator iter;
vector <int> G[MAX];
pair<int, int> st[MAX];
int dr, lvl[MAX], jos[MAX];

void extract(int nod, int fiu)
{
    int x, y;
    vector <int> v;
    while(nod != st[dr].first || fiu != st[dr].second)
    {
        v.push_back(st[dr].second);
        dr--;
    }
    v.push_back(fiu);
    v.push_back(nod);
    dr--;
    comp.push_back(v);
}

void df(int nod, int dad)
{
   // cout << nod << " ";
    lvl[nod] = lvl[dad] + 1;
    jos[nod] = lvl[nod];
    for(iter it = G[nod].begin() ; it != G[nod].end() ; it++)
    {

        if(*it == dad)
            continue;
        if(lvl[*it])
        {
            /// e deja vizitat(muchie de intoarcere)
            jos[nod] = min(jos[nod], lvl[*it]);
        }
        else
        {
            st[++dr] = make_pair(nod, *it);
            df(*it, nod);
            jos[nod] = min(jos[nod], jos[*it]);
            if(jos[*it] >= lvl[nod])
            {
                extract(nod, *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);
    fout << comp.size() << "\n";
    for(int i = 0 ; i < comp.size() ; i++)
    {
        for(iter it = comp[i].begin() ; it != comp[i].end() ; it++)
        {
            fout << *it << " ";
        }
        fout << "\n";
    }
}