#include <iostream>
#include <fstream>
#include <vector>
#include <stack>
#include <cstring>
#include <algorithm>
#define MAXN 100005
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,m,x,y;
vector <int> viz,low,ok;
stack <pair<int,int>> st;
vector <vector <int>> v(MAXN),afis;
void validatecompconx (const int a,const int b)
{
    //cout<<a<<' '<<b<<'\n';
    vector <int> ins;
    int insi,insj;
    do
    {
        insi=st.top().first,insj=st.top().second;
        st.pop();
        ins.push_back(insi);
        ins.push_back(insj);
    }while (insi!=a || insj!=b);
    afis.push_back(ins);
}
void dfs (const int cur,const int previous,int nr)
{
    vector <int> :: iterator it;
    viz[cur]=low[cur]=nr;
    for (int j=0; j<v[cur].size(); j++)
    {
        int next=v[cur][j];
        //cout<<cur<<' '<<viz[next]<<' '<<nr<<'\n';
        if (next!=previous)
        {
            //cout<<cur<<' '<<next<<' ';
            if (viz[next]==-1)
            {
               // cout<<1<<'\n';

                st.push(make_pair(cur,next));
                dfs(next,cur,nr+1);
                low[cur]=min(low[cur],low[next]);
                if (low[next]>=viz[cur])
                    validatecompconx(cur,next);

            }
            else
            {
                //cout<<2<<'\n';
                low[cur]=min(low[cur],viz[next]);
            }
        }
    }

}
int main()
{
    f>>n>>m;
    for (int i=1; i<=m; i++)
    {
        f>>x>>y;
       // cout<<x<<' '<<y<<'\n';
        v[x].push_back(y);
        v[y].push_back(x);
    }
    viz.resize(n+1);
    low.resize(n+1);
    ok.resize(n+1);
    for (int i=1; i<=n; i++)
        viz[i]=-1;
    dfs(1,0,0);
    g<<afis.size()<<'\n';
    for (int i=0; i<afis.size(); i++)
    {

        //memset(ok,0,sizeof(ok));
        sort(afis[i].begin(),afis[i].end());
        afis[i].erase(unique(afis[i].begin(),afis[i].end()),afis[i].end());
        for (int j=0; j<afis[i].size(); j++)
        {
            g<<afis[i][j]<<' ';
        }
        g<<'\n';
    }
    return 0;
}