#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
#include <stack>

using namespace std;

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

int n, m, nrcomp;
vector<int> gf[100001];
vector<pair<int, int>> muchii;
vector<vector<int>> comp;
int viz[100001], nivel[100001], nma[100001], ptart[100001];
stack<int> s;

void DFS_biconex(int k, int tata, int rad) {
    viz[k] = 1;
    nivel[k] = nivel[tata] + 1;
    nma[k] = nivel[k];
    s.push(k);
    int nrfii = 0;
    for (int x : gf[k])
        if (x != tata)
            if (!viz[x]) {
                nrfii++;
                DFS_biconex(x, k, rad);
                nma[k] = min(nma[k], nma[x]);

                // determinare puncte de articulație
                if (nivel[k] <= nma[x] && k != rad)
                    ptart[k] = 1;
                // determinare punți
                if (nivel[k] < nma[x])
                    muchii.push_back({ k, x });
                // determinare componente biconexe
                if (nivel[k] <= nma[x]) {
                    nrcomp++;
                    comp.push_back(vector<int>(0));
                    while (s.top() != x) {
                        comp[nrcomp - 1].push_back(s.top());
                        s.pop();
                    }
                    comp[nrcomp - 1].push_back(s.top());
                    s.pop();
                    comp[nrcomp - 1].push_back(k);
                }
            }
            else
                nma[k] = min(nma[k], nivel[x]);
    if (k == rad && nrfii > 1)
        ptart[k] = 1;
}

int main()
{
    fin >> n >> m;
    for (int i = 1; i <= m; i++) {
        int x, y;
        fin >> x >> y;
        gf[x].push_back(y);
        gf[y].push_back(x);
    }
    DFS_biconex(1, 0, 1);
    fout << nrcomp << "\n";
    for (int i = 0; i < nrcomp; i++) {
        for ( int j : comp[i])
            fout << j << " ";
        fout << "\n";
    }
    return 0;
}