#include <fstream>
#include <vector>
#include <algorithm>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");

typedef pair< int, int > edge;
int N, M, x, y, order, low[100002], found[100002], dad[100002];
vector <int> G[100002], Part;
vector < edge > CritEdge, st;
vector < vector < int > > BCC;

template <class T>
inline void ElimDuplicate(vector < T > &V)
{
    sort(V.begin(), V.end());
    V.erase( unique(V.begin(), V.end()), V.end());
}

void getbcc(edge M)
{
    vector <int> newbcc; edge E;
    do
    {
        E=st.back(); st.pop_back();
        newbcc.push_back(E.first); newbcc.push_back(E.second);
    } while (E!=M);
    ElimDuplicate(newbcc); BCC.push_back(newbcc);
}

void dfs(int nod)
{
    low[nod]=found[nod]=++order; int sons=0;
    vector < int >::iterator it=G[nod].begin();
    for (; it!=G[nod].end(); ++it)
        if (!dad[*it])
        {
            ++sons; dad[*it]=nod;
            st.push_back(edge(nod, *it));

            dfs(*it);

            if (!dad[nod] && sons>=2)
            {
                Part.push_back(nod); getbcc(edge(nod, *it));
                CritEdge.push_back(edge(nod, *it));
            }

            low[nod]=min(low[nod], low[*it]);
            if (low[*it]>=found[nod])
            {
                Part.push_back(nod); getbcc(edge(nod, *it));
                if (low[*it]>found[nod])
                    CritEdge.push_back(edge(nod, *it));
            }
        }
        else if (*it!=dad[nod])
            low[nod]=min(low[nod], found[*it]);
}

void tarjan()
{
    for (int i=1; i<=N; ++i)
        if (!dad[i]) dad[i]=i, dfs(i);
    ElimDuplicate(Part); ElimDuplicate(CritEdge);
}

int main()
{
    f>>N>>M;
    for (int i=1; i<=M; ++i)
        f>>x>>y, G[x].push_back(y), G[y].push_back(x);
    tarjan();
    g<<BCC.size()<<'\n';
    for (int i=0; i<(int)BCC.size(); ++i && g<<'\n')
        for (int j=0; j<BCC[i].size(); ++j)
            g<<BCC[i][j]<<' ';
    return 0;
}