#include <bits/stdc++.h>
using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

const int dim=1e5+9;

vector<int>v[dim];
stack<int>stiva;

int nr_comp_biconexe;
vector<int>comp_biconexe[dim];

bool vizitat[dim];
int disc[dim],low[dim];

void dfs(int x,int tata){

    vizitat[x]=true;
    low[x]=disc[x]=disc[tata]+1;
    stiva.push(x);

    for(int y:v[x]){
        if(y!=tata){
            if(!vizitat[y]){

                dfs(y,x);
                low[x]=min(low[x],low[y]);

                if(disc[x]<=low[y]){
                    nr_comp_biconexe++;
                    while(stiva.top()!=y){
                        comp_biconexe[nr_comp_biconexe].push_back(stiva.top());
                        stiva.pop();
                    }
                    comp_biconexe[nr_comp_biconexe].push_back(stiva.top());
                    stiva.pop();
                    comp_biconexe[nr_comp_biconexe].push_back(x);
                }
            }
            else{
                low[x]=min(low[x],disc[y]);
            }
        }
    }
}

signed main(){
    int n,m;
        fin>>n>>m;
    for(int i=1;i<=m;i++){
        int x,y;
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0);
        fout<<nr_comp_biconexe<<'\n';
    for(int i=1;i<=n;i++){
        for(int x:comp_biconexe[i]){
            fout<<x<<' ';
        }
        fout<<'\n';
    }
}