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

using namespace std;

vector <int> L[Nmax];
stack <int> St;
vector <int> Bcomp[2*Nmax]; /// o muchie apartine unei sg. componente biconexe
int Low[Nmax],N,nrcomp,Lvl[Nmax];
bool viz[Nmax];

inline void AddBcomp(int fnod, int nod)
{
    ++nrcomp;
    while(St.top()!=nod)
    {
        Bcomp[nrcomp].push_back(St.top()); St.pop();
    }
    Bcomp[nrcomp].push_back(nod); St.pop();
    Bcomp[nrcomp].push_back(fnod);
}

inline void Dfs(int nod, int lvl)
{
    vector <int> ::iterator it;
    viz[nod]=true; St.push(nod);
    Low[nod]=lvl; Lvl[nod]=lvl;
    for(it=L[nod].begin();it!=L[nod].end();++it)
        if(viz[*it])
            Low[nod]=min(Low[nod],Lvl[*it]);
        else
        {
            Dfs(*it,lvl+1);
            Low[nod]=min(Low[nod],Low[*it]);
            if(Low[*it]>=lvl)
                AddBcomp(nod,*it);
        }
}

int main()
{
    int M,x,y,i;
    freopen ("biconex.in","r",stdin);
    freopen ("biconex.out","w",stdout);
    scanf("%d%d", &N,&M);
    while(M--)
    {
        scanf("%d%d", &x,&y);
        L[x].push_back(y);
        L[y].push_back(x);
    }
    for(i=1;i<=N;++i)
        if(!viz[i])
            Dfs(i,0);
    printf("%d\n", nrcomp);
    for(i=1;i<=nrcomp;++i)
    {
        for(vector <int>::iterator it=Bcomp[i].begin();it!=Bcomp[i].end();++it)
            printf("%d ", *it);
        printf("\n");
    }
    return 0;
}