#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
using namespace std;
vector<int> V[100005];
int discovered[100005],low[100005],discovery=0;
int cntCompBic=0;
typedef vector<int> componentaBiconexa;
vector<componentaBiconexa> listCompBic;
stack<int> Stack;
void dfs(int k,int parent,int root)
{
    discovered[k]=low[k]=++discovery;
    Stack.push(k);
    for(auto x:V[k])
    if(x!=parent)
    {
        if(discovered[x]==0)
        {
            dfs(x,k,root);
            low[k]=min(low[k],low[x]);
            if(low[x]>=discovered[k])
            {
                //cout<<k<<" "<<x<<"\n";
                cntCompBic++;
                componentaBiconexa CB={};
                int go_back=-1;
                do
                {
                    go_back=Stack.top();
                    Stack.pop();
                    CB.push_front(go_back);
                }while(go_back!=x);
                CB.push_back(k);
                listCompBic.push_back(CB);
            }
        }
        else
            low[k]=min(low[k],discovered[x]);
    }
}
int main()
{
    ifstream fin("componentebiconexe.in");
    ofstream fout("componentebiconexe.out");
    int n,m,a,b;
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>a>>b;
        V[a].push_back(b);
        V[b].push_back(a);
    }
    for(int i=1;i<=n;i++)
        if(discovered[i]==0)
            dfs(i,-1,i);
    fout<<cntCompBic<<'\n';
    for(int i=0;i<cntCompBic;i++)
    {
        //fout<<listCompBic[i].size()<<" ";
        for(componentaBiconexa::iterator nod=listCompBic[i].begin();nod!=listCompBic[i].end();nod++)
            fout<<*nod<<" ";
        fout<<'\n';
    }
    return 0;
}