#include <fstream>
#include <vector>
#define K 100002
using namespace std;
ifstream fin("biconexe.in");
ofstream fout("biconexe.out");
int t,n,m,i,x,y,f[K],low[K],niv[K],cbc;
vector <int> v[K],stiva,C[K];
void dfs(int nod,int tata,int nivel){
    f[nod]=1;
    low[nod]=niv[nod]=nivel;
    stiva.push_back(nod);
    for(auto vecin : v[nod]){
        if(vecin==tata)continue;
        if(f[vecin]){
            low[nod]=min(low[nod],niv[vecin]);
            continue;
        }
        dfs(vecin,nod,nivel+1);
        low[nod]=min(low[nod],low[vecin]);
        if(low[vecin]>=niv[nod]){ ///detectez comp biconexa
            cbc++;
            int x=0;
            while(x!=vecin){
                x=stiva.back();
                stiva.pop_back();
                C[cbc].push_back(x);
            }
            C[cbc].push_back(nod);
        }
    }
}
int main(){
    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1,0,1);
    fout<<cbc<<"\n";
    for(i=1;i<=cbc;i++){
        for(auto x: C[i])
            fout<<x<<" ";
        fout<<"\n";
    }
    return 0;
}