#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;

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

const int NMAX = 100005;

int n, m, timp;
vector<int> g[NMAX];
vector<int> st;
vector< vector<int> > componente;
int niv[NMAX], low[NMAX];

void dfs(int nod, int tata)
{
    timp++;
    niv[nod] = timp;
    low[nod] = timp;
    st.push_back(nod);

    for (int i = 0; i < (int)g[nod].size(); i++)
    {
        int vecin = g[nod][i];

        if (vecin == tata)
            continue;

        if (niv[vecin] != 0)
        {
            low[nod] = min(low[nod], niv[vecin]);
        }
        else
        {
            dfs(vecin, nod);
            low[nod] = min(low[nod], low[vecin]);

            if (low[vecin] >= niv[nod])
            {
                vector<int> comp;
                int x;
                do
                {
                    x = st.back();
                    st.pop_back();
                    comp.push_back(x);
                } while (x != vecin);
                comp.push_back(nod);
                componente.push_back(comp);
            }
        }
    }
}

int main()
{
    fin >> n >> m;

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

    for (int i = 1; i <= n; i++)
        if (niv[i] == 0)
            dfs(i, 0);

    fout << componente.size() << "\n";
    for (int i = 0; i < (int)componente.size(); i++)
    {
        for (int j = 0; j < (int)componente[i].size(); j++)
            fout << componente[i][j] << " ";
        fout << "\n";
    }

    return 0;
}