#include <cstdio>
#include <stack>
#include <vector>
#define nmax 100005

using namespace std;

int n,m,nivel[nmax],nr;
vector<int> g[nmax],sol[nmax];
stack<pair<int,int> >st;
bool viz[nmax];

void solutie(int x,int y)
{
    ++nr;
    int xx=st.top().first;
    int yy=st.top().second;
    while(xx!=x&&yy!=y)
    {
        st.pop();
        sol[nr].push_back(yy);
        xx=st.top().first;
        yy=st.top().second;
    }
    sol[nr].push_back(xx);
    sol[nr].push_back(xx);
    st.pop();
}

void dfs(int k,int tata,int niv,int &niv_min)
{
    if(viz[k])
        niv_min=nivel[k];
    else
    {
        int aux;
        niv_min=niv;
        nivel[k]=niv;
        viz[k]=1;
        for(vector<int>::iterator ii=g[k].begin();ii!=g[k].end();++ii)
            if(*ii!=tata)
            {
                if(viz[*ii])
                    dfs(*ii,k,niv+1,aux);
                else
                {
                    st.push(make_pair(k,*ii));
                    dfs(*ii,k,niv+1,aux);
                    if(aux>=niv)
                        solutie(k,*ii);
                }
                if(aux<niv_min)
                    niv_min=aux;
            }
    }
}

void citire()
{
    int x,y;
    scanf("%d%d",&n,&m);
    for(int i=1;i<=m;i++)
    {
        scanf("%d%d",&x,&y);
        g[x].push_back(y);
        g[y].push_back(x);
    }
}

void afisare()
{
    printf("%d\n",nr);
    for(int i=1;i<=nr;i++)
    {
        for(vector<int>::iterator ii=sol[i].begin();ii!=sol[i].end();++ii)
            printf("%d ",*ii);
        printf("\n");
    }
}

int main()
{
    freopen("biconex.in","r",stdin);
    freopen("biconex.out","w",stdout);
    citire();
    int aux;
    dfs(1,-1,1,aux);
    afisare();
    return 0;
}