#include <iostream>
#include <cstdio>
#include <vector>
#include <stack>
#include <bitset>

#define mp make_pair

using namespace std;

const int NodMax = 100005;
const int MuchMax = 200005;
int N, M, comp_biconexe, time;
int tov[NodMax], low[NodMax];
bitset < NodMax > viz;
stack < pair < int, int >  > st;
vector < int > G[NodMax], rez[NodMax];
//tov = time of visit = cand gasesc prima oara nodul x
//low = nivel cel mai mic la care poate ajunge nodul x

void Read()
{
    scanf("%d %d", &N, &M);

    for(int i=1; i<=M; ++i)
    {
        int x, y;
        scanf("%d %d", &x, &y);
        G[x].push_back(y);
        G[y].push_back(x);
    }
}

void Solve(int nod)
{
    int nr = comp_biconexe;

     while(!st.empty() && st.top().second!=nod)
    {
      rez[nr].push_back(st.top().second);
      st.pop();
    }

    rez[nr].push_back(st.top().second);
    rez[nr].push_back(st.top().first);
    st.pop();
}

void DFS(int nod, int dad)
{
   tov[nod] = low[nod] = 1 + time;
   ++time;
   viz[nod] = 1;
   vector < int > ::iterator it;
   for(it=G[nod].begin(); it!=G[nod].end(); ++it)
   {
       if(*it == dad)
            continue;

       else
            if(!viz[*it])
       {
           st.push(mp(nod,*it));

           DFS(*it,nod);

           low[nod] = min(low[nod], low[*it]);

           if(low[*it] >= tov[nod])
           {
               ++comp_biconexe;
               Solve(*it);
           }

       }

        else
        {
            low[nod] = min(low[nod], tov[*it]);
        }
   }
}

int main()
{
    freopen("biconex.in", "r", stdin);
    freopen("biconex.out", "w", stdout);
    Read();

    for(int i=1; i<=N; ++i)
    {
        if(!viz[i])
        {
            DFS(i,0);
        }
    }

    cout << comp_biconexe << "\n";

    for(int i=1; i<=comp_biconexe; ++i)
    {
        vector < int > ::iterator it;
        for(it=rez[i].begin(); it!=rez[i].end(); ++it)
            cout << *it << " ";

        cout<<"\n";
    }

    return 0;
}