# include <fstream>
# include <vector>
# include <stack>
# define DIM 100010
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
vector<int> Lista[DIM],nr[DIM],sol[DIM];
stack<pair<int,int> > s;
pair<int,int> a;
int low[DIM],poz[DIM],n,m,nsol,i,j,x,y;
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(nv,nc));
            biconex(nv,nc,niv+1);
            if(low[nv]>=poz[nc]){
                nsol++;
                for(;;){
                    a=s.top();
                    s.pop();
                    x=a.first;
                    y=a.second;
                    sol[nsol].push_back(x);
                    if(x==nv&&y==nc)
                        break;
                }
                sol[nsol].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<<nsol<<"\n";
    for(i=1;i<=nsol;i++){
        for(j=0;j<sol[i].size();j++)
            fout<<sol[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}