#include <iostream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <queue>
#include <stack>

#define vt vector
#define pb push_back
#define sz(x) (int)(x).size()
#define all(x) (x).begin(), (x).end()
#define pii pair <int, int>

#define fr first 
#define sc second

using namespace std;

string filename = "biconex";
ifstream fin(filename + ".in");
ofstream fout(filename + ".out");

////////////////////////////////////////////////////////////


const int NMAX = 1e5;

vt <int> adj[NMAX + 1];

stack <int> S;
bool viz[NMAX + 1];

int lvl[NMAX + 1];
int ll[NMAX + 1];

vt <vt <int>> comps;

void dfs(int node, int par){
    viz[node] = 1;
    S.push(node);
    ll[node] = lvl[node] = lvl[par] + 1;

    for(int vec : adj[node]){
        if(vec != par){
            if(viz[vec]){
                ll[node] = min(ll[node], lvl[vec]);
            }else{
                dfs(vec, node);
                ll[node] = min(ll[node], ll[vec]);

                if(ll[vec] >= lvl[node]){
                    vt <int> aux;

                    while(S.top() != vec){
                        aux.pb(S.top());
                        S.pop();
                    }
                    aux.pb(S.top());
                    S.pop();
                    aux.pb(node);
                    comps.pb(aux);
                }
            }
        }
    }
}

void solve(){
    int n, m;
    fin >> n >> m;

    for(int i = 1; i <= m; i++){
        int a, b;
        fin >> a >> b;
        adj[a].pb(b);
        adj[b].pb(a);
    }

    dfs(1, 0);

    fout << sz(comps) << '\n';
    for(vt <int> comp : comps){
        for(int x : comp){
            fout << x << ' ';
        }
        fout << '\n';
    }
}

int main(){

    int T;
    //fin >> T;

    T = 1;

    while(T--){
        solve();
    }

    return 0;
}