#include <fstream>
#include <stack>
#include <vector>
#define nmax 100002
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");

vector <int> graf[nmax];
vector <int> sol[nmax];
stack <int> st;
int father[nmax],vizitat[nmax],nivel[nmax],low[nmax],nr=1,n,m,x,y;

void dfs(int nod)
{
    vizitat[nod]=1;
    nivel[nod]=nivel[father[nod]]+1;
    low[nod]=nivel[nod];
    st.push(nod);
    for(int i=0;i<graf[nod].size();i++)
    {
        int z=graf[nod][i];
        if(vizitat[z])
        {
            if(z!=father[nod])
                low[nod]=min(low[nod],nivel[z]);
            continue;
        }
        father[z]=nod;
        dfs(z);
        low[nod]=min(low[nod],low[z]);
        if(nivel[nod]<=low[z])
        {
            int k;
            do
            {
                k=st.top();
                sol[nr].push_back(k);
                st.pop();
            }while(k!=z);
            sol[nr].push_back(nod);
            nr++;
        }
    }
}


int main()
{
    fin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
    {
        if(!vizitat[i])
        {
            father[i]=0;
            dfs(i);
        }
    }
    fout<<nr-1<<"\n";
    for(int i=1;i<nr;i++)
    {
        for(int j=sol[i].size()-1;j>=0;j--)
            fout<<sol[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}