#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <algorithm>
#define dMAX 100000

using namespace std;

int n, m, x, y, idx;
vector<int> graf[dMAX + 2];
vector<int> cBiconexe[dMAX + 2];
stack<int> vBiconexe;
bool viz[dMAX + 2];
int level[dMAX + 2], nma[dMAX + 2];

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

void DFS(int v, int pv) {
    viz[v] = true;
    vBiconexe.push(v);
    level[v] = level[pv] + 1;
    nma[v] = level[v];
    int newV, u;
    for (u = 0; u < graf[v].size(); u++) {
        newV = graf[v][u];
        if (!viz[newV]) {
            DFS(newV, v);
            nma[v] = min(nma[v], nma[newV]);
            if (level[v] <= nma[newV]) {
                idx++;
                while (vBiconexe.top() != newV && !vBiconexe.empty()) {
                    cBiconexe[idx].push_back(vBiconexe.top());
                    vBiconexe.pop();
                }
                cBiconexe[idx].push_back(newV);
                if (!vBiconexe.empty())
                vBiconexe.pop();
                cBiconexe[idx].push_back(v);
                sort(cBiconexe[idx].begin(), cBiconexe[idx].end());
            }
        } else {
            if (newV != pv) {
                nma[v] = min(nma[v], level[newV]);
            }
        }
    }
}

int main()
{
    int i, j;
    fin >> n >> m;
    for (i = 1; i <= m; i++) {
        fin >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    DFS(1, 0);
    fout << idx << '\n';
    for (i = 1; i <= idx; i++) {
        for (j = 0; j < cBiconexe[i].size(); j++) {
            fout << cBiconexe[i][j] << ' ';
        }
        fout << '\n';
    }

    return 0;
}