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

using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");

vector<int>graph[100005];

stack<int>s;

vector<int>rez[100005];

int k;

bool viz[100005];
int llk[100005], ix[100005];

int n, m, x, y;

void citire()
{
    f >> n >> m;
    for (int i=0; i<m; ++i)
    {
        f >> x >> y;
        graph[x].push_back(y);
        graph[y].push_back(x);
    }
}

void parcurgere(int ind, int parinte)
{
    viz[ind]=1;
    //llk[ind]=ix[ind]=1;
    for (auto &v:graph[ind])
    {
        if (!viz[v] && v!=parinte)
        {
            ix[v]=ix[ind]+1;
            llk[v]=ix[v];
            s.push(v);
            parcurgere(v,ind);
            llk[ind]=min(llk[ind],llk[v]);
            if (llk[v]>=ix[ind])
            {
                //rez[k].resize(0);
                while (s.top()!=v)
                {
                    rez[k].push_back(s.top());
                    s.pop();
                }
                rez[k].push_back(s.top());
                s.pop();
                rez[k].push_back(ind);
                k++;

            }

        }
        else if (viz[v])
        {
            llk[ind]=min(llk[ind],ix[v]);
        }
    }
}

int main()
{
    citire();
    for (int i=1; i<=n; ++i)
    {
        if (!viz[i])
        {
            parcurgere(i,0);
        }
    }
    g << k << '\n';
    for (int i=0; i<k; ++i)
    {
        for (auto &v:rez[i])
        {
            g << v <<' ';
        }
        g << '\n';
    }
    return 0;
}