#include <bits/stdc++.h>
#define DIM 100005

using namespace std;

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

int n, m, i, j, a, b, cnt, cnt2, cnt3;
int f[DIM], niv[DIM], low[DIM], v[DIM], sol[DIM];

vector <int> L[DIM], comp[DIM];

stack <int> stiva;

void dfs (int nod, int tata, int nivel){
    int x;
    f[nod] = 1;
    niv[nod] = nivel;
    low[nod] = nivel;
    stiva.push(nod);
    for (int i=0; i<L[nod].size(); i++){
        int vecin = L[nod][i];
        if (nod == tata)
            continue;
        if (f[vecin] == 1){
            low[nod] = min (low[nod], niv[vecin]);
        }
        else{
            dfs(vecin, nod, nivel + 1);
            low[nod] = min (low[nod], low[vecin]);
            if (low[vecin] >= niv[nod]){
                v[nod]++;
                cnt++;
                do{
                    x = stiva.top();
                    comp[cnt].push_back(x);
                    stiva.pop();
                }while (x != vecin);
                comp[cnt].push_back(nod);
            }
        }
    }
}

int main(){
    fin >> n >> m;
    for (i=1; i<=m; i++){
        fin >> a >> b;
        L[a].push_back(b);
        L[b].push_back(a);
    }
    dfs (1, 0, 1);
    fout << cnt << "\n";
    for (i=1; i<=cnt; i++){
        for (j=0; j<comp[i].size(); j++){
            fout << comp[i][j] << " ";
        }
        fout << "\n";
    }
    return 0;
}