# include <fstream>
# include <vector>
# include <stack>
# define DIM 100010
# define f first
# define s second
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
vector<int> Lista[DIM],cb[DIM];
stack<pair<int,int> > S;
pair<int,int> a;
int Marcat[DIM],low[DIM],poz[DIM],n,m,x,y,i,j,nrb;
void biconex(int nc,int tata,int niv){
    poz[nc]=low[nc]=niv;
    for(int i=0;i<Lista[nc].size();i++){
        int nv=Lista[nc][i];
        if(poz[nv]==0){
            S.push(make_pair(nc,nv));
            biconex(nv,nc,niv+1);
            if(low[nv]>=poz[nc]){
                nrb++;
                for(;;){
                    a=S.top();
                    S.pop();
                    cb[nrb].push_back(a.s);
                    if(a.f==nc&&a.s==nv)
                        break;
                }
                cb[nrb].push_back(nc);
            }
            else
                low[nc]=min(low[nc],low[nv]);
        }
        else{
            if(nv!=tata)
                low[nc]=min(low[nc],poz[nv]);
        }
    }
}
int main () {
    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>x>>y;
        Lista[x].push_back(y);
        Lista[y].push_back(x);
    }
    biconex(1,0,1);
    fout<<nrb<<"\n";
    for(i=1;i<=nrb;i++){
        for(j=0;j<cb[i].size();j++)
            fout<<cb[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}