#define MAX_N 100000

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

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

int n, m, cb, timp, vizitat[MAX_N + 1];
vector<int> G[MAX_N + 1];
vector<int> C[MAX_N + 1];

int Df(int nod);

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

    for (int i = 1, x, y; i <= m; ++i)
    {
        fin >> x >> y;

        G[x].push_back(y);
        G[y].push_back(x);
    }

    for (int i = 1; i <= n; ++i)
    {
        if (vizitat[i] == 0)
        {
            Df(i);
        }
    }

    fout << cb << '\n';

    for (int i = 1; i <= cb; ++i)
    {
        for (int nod : C[i])
        {
            fout << nod << ' ';
        }
        fout << '\n';
    }


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

bitset<MAX_N + 1> f;
void Solutie(int nod)
{
    if (f[nod]) { return; }
    f[nod] = true;
    C[cb].push_back(nod);

    for (int vecin : G[nod])
    {
        Solutie(vecin);
    }
}

int Df(int nod)
{
    vizitat[nod] = ++timp;

    int res = vizitat[nod];
    for (int vecin : G[nod])
    {
        if (vizitat[vecin] == 0)
        {
            int res_vecin = Df(vecin);

            res = min(res, res_vecin);

            if (res_vecin == vizitat[vecin])
            {
                ++cb;

                C[cb].push_back(nod);
                C[cb].push_back(vecin);
                f[vecin] = true;
            }

            if (res_vecin == vizitat[nod])
            {
                ++cb;

                f[nod] = true;
                C[cb].push_back(nod);
                Solutie(vecin);
                f[nod] = false;
            }
        }
        else
        {
            if (vizitat[vecin] != (vizitat[nod] - 1))
            {
                res = min(res, vizitat[vecin]);
            }
        }
    }

    return res;
}