#include <vector>
#include <algorithm>
#include <fstream>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int k, t , i, p, q;
int H[100005], up[100005];
bool viz[100005];
int stiva[2][100005];
vector <int> V[100005], S[100005];
vector <int>::iterator it;
void citire(){
    f >> t >> t;
    for (i = 1; i <= t; i++) {
        f>>p>>q;
        V[p].push_back(q);
        V[q].push_back(p);
    }
}
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][++t] = nod;
            stiva[1][t] = *it;
            dfs(*it);
            if (up[*it] >= H[nod]) {
                k++;
                while (!(stiva[0][t] == nod && stiva[1][t] == *it)) {
                    S[k].push_back(stiva[1][t]);
                    t--;
                }
                S[k].push_back(nod);
                S[k].push_back(*it);
                t--;
            }
            up[nod] = min(up[nod], up[*it]);
        }
        else
            up[nod] = min(up[nod], H[*it]);
}
void afisare() {
     g << k << '\n';
    for(i = 1; i <= k; i++){
        sort(S[i].begin(),S[i].end());
        for(it = S[i].begin(); it != S[i].end(); ++it)
            g << *it << " ";
        g << '\n';
    }
}
int main() {
    citire();
    dfs(1);
    afisare();
}