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

using namespace std;

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

const int NMAX = 100000 + 5;
const int INF = 0x3f3f3f3f;

vector <int> graph[NMAX], t[NMAX], comp[NMAX];
stack <int> s;
int n, m, top, nr;
int niv[NMAX], fat[NMAX], st[NMAX], nivmin[NMAX];
bool vis[NMAX];

void dfs(int node)
{
    vis[node] = true;
    niv[node] = niv[fat[node]] + 1;
    for (int i: graph[node])
        if (!vis[i])
        {
            fat[i] = node;
            t[node].push_back(i);
            s.push(i);
            dfs(i);
            if (nivmin[i] >= niv[node])
            {
                ++nr;
                while (s.top() != i)
                {
                    comp[nr].push_back(s.top());
                    s.pop();
                }
                comp[nr].push_back(s.top());
                s.pop();
            }
        }

    int minim = INF;
    for (int i: t[node]) minim = min(minim, nivmin[i]);
    for (int i: graph[node]) minim = min(minim, niv[i]);

    nivmin[node] = minim;
}

void write()
{
    fout << nr << '\n';
    for (int i = 1; i <= nr; ++i)
    {
        for (int j: comp[i])
            fout << j << " ";
        fout << fat[comp[i][comp[i].size() - 1]] << '\n';
    }
}

void read()
{
    int x, y;

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

int main()
{
    read();
    dfs(1);
    write();

    return 0;
}