#include<bits/stdc++.h>
#define nmax 100002
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
vector <int> v[nmax];
vector <int> sol[nmax];
deque<int> st;
int viz[nmax],nivel[nmax],low[nmax],t[nmax],nr=1,n,m,x,y;
void df(int nod)
{
    viz[nod]=1;
    nivel[nod]=nivel[t[nod]]+1;
    low[nod]=nivel[nod];
    st.push_front(nod);
    for(int i=0;i<v[nod].size();i++)
    {
        int p=v[nod][i];
        if(viz[p])
        {
            if(p!=t[nod])
                low[nod]=min(low[nod],nivel[p]);
            continue;
        }
        t[p]=nod;
        df(p);
        low[nod]=min(low[p],low[nod]);
        if(nivel[nod]<=low[p])
        {
            int k;
            do
            {
                k=st[0];
                sol[nr].push_back(k);
                st.pop_front();
            }
            while(k!=p);
            sol[nr].push_back(nod);
            nr++;
        }
    }
}

int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
        if(viz[i]==0)
        {
            t[i]=0;
            df(i);
        }
    g<<nr-1<<"\n";
    for(int i=1;i<nr;i++)
    {
        for(int j=0;j<sol[i].size();j++)
           g<<sol[i][j]<<" ";
        g<<"\n";
    }
    return 0;
}