#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <queue>
#include <vector>
#include <stack>
#define MAXN 100005
#define MAXM 200005
#define INFI 1000000
using namespace std;

struct XYZ{
  int x,y;
};

vector <int> graf[MAXN];
vector <int> answ[MAXN];
stack <int> parc;
int visi[MAXN];
int adan[MAXN];
int mini[MAXN];
int t,ans;

void AddEdge(XYZ a){
  graf[a.x].push_back(a.y);
  graf[a.y].push_back(a.x);
}

void DFS(int node,int fath){
  int c;
  visi[node]=1;
  adan[node]=t;
  mini[node]=t;
  parc.push(node);
  t++;
  c=0;
  for(int neigh : graf[node]){
    if(visi[neigh]==0){
      DFS(neigh,node);
      if(mini[node]>mini[neigh]){
        mini[node]=mini[neigh];
      }
      if(mini[neigh]>=adan[node]){
        while(parc.top()!=neigh){
          answ[ans].push_back(parc.top());
          parc.pop();
        }
        answ[ans].push_back(neigh);
        parc.pop();
        answ[ans].push_back(node);
        ans++;
      }
      c++;
    }else{
      if(fath!=neigh && adan[neigh]<adan[node]){
        if(mini[node]>adan[neigh]){
          mini[node]=adan[neigh];
        }
      }
    }
  }
}

int main(){
  int n,m,i,x,y;
  FILE *fin,*fout;
  fin=fopen("biconex.in","r");
  fout=fopen("biconex.out","w");
  fscanf(fin,"%d%d",&n,&m);

  for(i=0;i<m;i++){
    fscanf(fin,"%d%d",&x,&y);
    AddEdge({x,y});
  }

  t=0;
  ans=0;
  DFS(1,-1);

  fprintf(fout,"%d\n",ans);

  for(i=0;i<ans;i++){
    for(int r:answ[i]){
      fprintf(fout,"%d ",r);
    }
    fprintf(fout,"\n");
  }

  fclose(fin);
  fclose(fout);
  return 0;
}