#include <vector>
#include <algorithm>
#include <fstream>
#include <iostream>
using namespace std;
ifstream in("biconex.in");
ofstream out("biconex.out");
int k, n,m , i, p, q;
int H[100005], up[100005];
bool viz[100005];
int stiva[2][100005];
vector <int> v[100005], b[100005];
vector <int>::iterator it;
void citire(){
}
void dfs(int nod) {
    viz[nod] = true;
    up[nod] = H[nod];
    for (vector <int>::iterator it = v[nod].begin(); it != v[nod].end(); ++it)
        if (viz[*it] == false){
            H[*it] = H[nod] + 1;
            stiva[0][++m] = nod;
            stiva[1][m] = *it;
            dfs(*it);
            if (up[*it] >= H[nod]) {
                k++;
                while (!(stiva[0][m] == nod && stiva[1][m] == *it)) {
                    b[k].push_back(stiva[1][m]);
                    m--;
                }
                b[k].push_back(nod);//aici adaugam grafurile biconvexe
                b[k].push_back(*it);
                m--;
            }
            up[nod] = min(up[nod], up[*it]);
        }
        else
            up[nod] = min(up[nod], H[*it]);
}
void afisare() {
    out << k << '\n';
    for(i = 1; i <= k; i++){
        for(it = b[i].begin(); it != b[i].end(); ++it)
            out << *it << " ";
        out << '\n';
    }
}
int main() {
    in >> n >> m;
    for (i = 1; i <= m; i++) {
        in>>p>>q;
        v[p].push_back(q);
        v[q].push_back(p);
    }
    m = 0;
    dfs(1);
    afisare();
}