#include <fstream>
#include <vector>
#include <set>
#include <stack>

using namespace std;

const int NMAX=100005;

vector<int> graph[NMAX];
vector<int> discover, low, parent;
vector<int> biconexe[NMAX];

struct muchie
{
    int nod1, nod2;
};

stack<muchie> st;
int timp, n, nr;

void componenta(int x, int y) {

    int i, j;
    nr++;
    do {
        i = st.top().nod1;
        j = st.top().nod2;
        st.pop();
        biconexe[nr].push_back(j);
    } while(i != x && j != y);

    biconexe[nr].push_back(x);
}

void dfs(int nod) {

    muchie aux{};
    timp++;
    discover[nod] = low[nod] = timp;
    for(auto &fiu : graph[nod]) {
        if(parent[fiu] != nod) {
            if(!discover[fiu]) {
                aux.nod1 = nod;
                aux.nod2 = fiu;
                st.push(aux);
                parent[fiu] = nod;

                dfs(fiu);

                if(low[fiu] >= discover[nod]) {
                    componenta(nod, fiu);
                }

                low[nod] = min(low[nod], low[fiu]);
            }
            else {
                low[nod] = min(low[nod], discover[fiu]);
            }
        }
    }
}

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

    int m, u, v;
    fin >> n >> m;
    for(int i = 1; i <= m; i++) {
        fin >> u >> v;
        graph[u].push_back(v);
        graph[v].push_back(u);
    }

    parent.resize(n+1, 0);
    low.resize(n+1, 0);
    discover.resize(n+1, 0);

    for(int i = 1; i <= n; i++) {
        if(!discover[i])
            dfs(i);
    }

    fout << nr << "\n";

    for(int i = 1; i <= nr; i++) {
        for(auto &elem : biconexe[i]) {
            fout << elem << " ";
        }
        fout << "\n";
    }

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