#include <fstream>
#include <vector>
#include <algorithm>

#define NMAX 100000

using namespace std;

ifstream cin("biconexe.in");
ofstream cout("biconexe.out");

struct maca{
  int a, b;
}stiva[NMAX + 1];
int k, globalTime = 0;

struct type_node {
  int d, l;
  vector<int>edge;
}graf[NMAX + 1];

int nrComp;
vector<int>comp[NMAX + 1];

void findComp(int nod) {
  nrComp++;
  while(stiva[k].a != nod) {
    comp[nrComp].push_back(stiva[k].b);
    k--;
  }
  comp[nrComp].push_back(stiva[k].b);
  comp[nrComp].push_back(stiva[k].a);
  k--;
}

void dfs(int p, int nod) {
  globalTime++;
  graf[nod].d = graf[nod].l = globalTime;
  for(auto copil : graf[nod].edge) {
    if(copil == p) {
      continue;
    }
    if(graf[copil].d == 0) {
      k++;
      stiva[k].a = nod;
      stiva[k].b = copil;
      dfs(nod, copil);
      graf[nod].l = min(graf[nod].l, graf[copil].l);
      if(graf[nod].d <= graf[copil].l) {
        findComp(nod);
      }
    } else {
      graf[nod].l = min(graf[nod].l, graf[copil].d);
    }
  }
}

signed main() {
  int n, m;
  cin>>n>>m;
  while(m--) {
    int a, b;
    cin>>a>>b;
    graf[a].edge.push_back(b);
    graf[b].edge.push_back(a);
  }
  dfs(0, 1);
  cout<<nrComp<<"\n";
  for(int i = 1; i <= nrComp; i++) {
    for(int j = 0; j < comp[i].size(); j++) {
      cout<<comp[i][j]<<" ";
    }
    cout<<"\n";
  }
  return 0;
}