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

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

template < class T>
inline void EliminaDuplicate(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.pb(E.first); newbcc.pb(E.second);
    }while (E!=M);
    EliminaDuplicate(newbcc);
    BCC.pb(newbcc);
}

void dfs(int nod)
{
    low[nod]=found[nod]=++order;
    vector < int > :: iterator it=G[nod].begin();
    for  (; it!=G[nod].end(); ++it)
        if (!dad[*it])
        {
            dad[*it]=nod; st.pb(edge(nod, *it));
            dfs(*it);
            low[nod]=min(low[nod], low[*it]);
            if (low[*it]>=found[nod])
            {
                Part.pb(nod); getbcc(edge(nod, *it));
                if (low[*it]>found[nod])
                    CritEdge.pb(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);
    EliminaDuplicate(Part);
    EliminaDuplicate(CritEdge);
}

void printBCC()
{
    g<<BCC.size()<<'\n';
    for (int i=0; i<(int)BCC.size(); ++i && g<<'\n')
        for (int j=0; j<(int)BCC[i].size(); ++j)
            g<<BCC[i][j]<<' ';
}

int main()
{
    f>>N>>M;
    for (int i=1; i<=M; ++i)
        f>>x>>y, G[x].pb(y), G[y].pb(x);

    tarjan(); printBCC();
    return 0;
}