#include <iostream>
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#define MAXN 100005
using namespace std;

struct XYZ{
  int x,y;
};

vector <int> graf[MAXN];
int adan[MAXN];
int jump[MAXN];
vector <int> ans[MAXN];
vector <int> parc;
int k;



void DFS(int node,int jos,int fath){
  int sarit;

  jump[node]=jos;
  adan[node]=jos;
  parc.push_back(node);
  sarit=jos;
  for(int neigh : graf[node]){
    if(neigh!=fath){
      if(adan[neigh]==0){
        DFS(neigh,jos+1,node);
      }
      sarit=min(sarit,jump[neigh]);
      if(jump[neigh]>=adan[node]){
        int s=0;
        while(parc.back()!=node){
          ans[k].push_back(parc.back());
          parc.pop_back();
          s=1;
        }
        if(s==1){
          ans[k].push_back(node);
          k++;
        }
      }
    }
  }
  //parc.pop_back();

  jump[node]=sarit;
}

int main(){
  int n,m,i,x,y,c;
  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);
    graf[x].push_back(y);
    graf[y].push_back(x);
  }

  DFS(1,1,-1);

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

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

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