/// 15:26 - 15:40
#include <bits/stdc++.h>
#define DIM 100010
using namespace std;

ifstream fin ("biconex.in");
ofstream fout ("biconex.out");
vector <int> L[DIM],sol[DIM];
int low[DIM],niv[DIM],viz[DIM];
deque <int> s;
int n,m,x,y,i,nr_comp;
void dfs (int nod, int tata){
    viz[nod] = 1;
    low[nod] = niv[nod] = 1+niv[tata];
    s.push_back(nod);
    for (int i=0;i<L[nod].size();i++){
        int vecin = L[nod][i];
        if (vecin == nod)
            continue;
        if (viz[vecin])
            low[nod] = min (low[nod],niv[vecin]);
        else {
            dfs (vecin,nod);
            low[nod] = min (low[nod],low[vecin]);
            if (low[vecin] >= niv[nod]){
                /// am componenta
                nr_comp++;
                sol[nr_comp].push_back(nod);
                int x;
                do{
                    x = s.back();
                    sol[nr_comp].push_back(x);
                    s.pop_back();
                } while (x != vecin);
            }}}}
int main (){

    fin>>n>>m;
    for (i=1;i<=m;i++){
        fin>>x>>y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
    for (i=1;i<=n;i++)
        if (!viz[i])
            dfs (i,0);

    fout<<nr_comp<<"\n";
    for (i=1;i<=nr_comp;i++){
        for (auto it:sol[i])
            fout<<it<<" ";
        fout<<"\n";
    }


    return 0;
}