#include <bits/stdc++.h>

#define inf 100000000000000

using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

int level[100005];
int low[100005], root;
int tata[100005], n;
vector<int> L[100005];
///vector<pair<int, int>> edges;
vector< set<int> > Componente;
bitset<100005> viz;
///bitset<100005> NodCritic;
stack< pair<int, int> > st;

void Citire() {
    int m, x, y;

    fin >> n >> m;
    for(int i = 1; i <= m; i++) {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);

    }
}

void ComponenteBiconexe(int x, int y) {
    int tx, ty;
    set<int> aux;

    do {
        tx = st.top().first;
        ty = st.top().second;
        st.pop();
        aux.insert(tx);
        aux.insert(ty);
    } while(x != tx && y != ty);

    Componente.push_back(aux);
}

void Dfs(int nod) {
    level[nod] = level[tata[nod]] + 1;
    low[nod] = level[nod];
    viz[nod] = 1;
    for(int i : L[nod])
        if(i != tata[nod]) {
            if(viz[i] == 1)
                low[nod] = min(level[i], low[nod]);
            else {
                tata[i] = nod;
                st.push({nod, i});
                Dfs(i);
                low[nod] = min(low[nod], low[i]);
                if(level[nod] <= low[i])
                    ComponenteBiconexe(nod, i);
            }
        }
}

void Afis() {
    fout << Componente.size() << "\n";

    for(auto e : Componente) {
        for(int i : e)
            fout << i << " ";
        fout << "\n";
    }
}

void Solution() {
    for(int i = 1; i <= n; i++)
        if(!viz[i]) Dfs(i);
      Afis();
}

int main() {
    ios_base :: sync_with_stdio(0);
    fin.tie(0);
    fout.tie(0);

    Citire();
    Solution();

    fin.close();
    fout.close();
    return 0;
}