#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
#define MAX 100010
#define cout fout
vector < vector <int> > cb;
typedef vector <int> :: iterator iter;
vector <int> G[MAX];
pair <int, int> st[2 * MAX];
int dr, lg, depth[MAX], h[MAX], viz[MAX];
void catch_bc(int x, int y)
{
    vector <int> aux;
    while(st[dr] != make_pair(x, y))
    {
        aux.push_back(st[dr].second);
        dr--;
    }
    aux.push_back(y);
    aux.push_back(x);
    dr--;
    cb.push_back(aux);
}

void df(int nod, int dad)
{
    viz[nod] = 1;
    lg++;
    depth[nod] = lg;
    h[nod] = lg;
    for(iter it = G[nod].begin() ; it != G[nod].end() ; it++)
    {
        if(*it == dad)
            continue;

        if(viz[*it])
        {
            h[nod] = min(h[nod], depth[*it]);
        }
        else
        {
            st[++dr] = make_pair(nod, *it);
            df(*it, nod);
            h[nod] = min(h[nod], h[*it]);
            if(h[*it] >= depth[nod])
            {
                catch_bc(nod, *it);
            }
        }
    }
    lg--;
}

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