#include <fstream>
#include <algorithm>
#include <vector>
#include <bitset>
#include <deque>
#define dim 100001
using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

int n,m,i,j,niv[dim],low[dim],cnt,x;
bitset <dim> f;
vector <int> l[dim],c[dim];
deque <int> q;

void dfs(int nod, int tata){
    f[nod]=1;
    niv[nod]=1+niv[tata];
    low[nod]=niv[nod];
    q.push_back(nod);

    for(int i=0;i<l[nod].size();i++){
        int vec=l[nod][i];

        if(vec==tata)
            continue;

        if(f[vec]==1){
            low[nod]=min(low[nod],niv[vec]);
        }else{
            dfs(vec,nod);
            low[nod]=min(low[nod],low[vec]);

            if(low[vec]>=niv[nod]){
                cnt++;
                do{
                    x=q.back();
                    q.pop_back();
                    c[cnt].push_back(x);
                }while(x!=vec);
                c[cnt].push_back(nod);
            }
        }
    }
}

int main(){
    fin>>n>>m;
    for(;m;m--){
        fin>>i>>j;
        l[i].push_back(j);
        l[j].push_back(i);
    }

    niv[1]=1;
    dfs(1,0);

    for(i=1;i<=cnt;i++)
        sort(c[i].begin(),c[i].end());

    fout<<cnt<<"\n";
    for(i=1;i<=cnt;i++,fout<<"\n"){
        for(j=0;j<c[i].size();j++)
            fout<<c[i][j]<<" ";
    }

    return 0;
}