#include <iostream>
#include <fstream>
#include <vector>
#include <deque>

using namespace std;

void DFS( int k, int tata, vector < int > &v, vector < int > &nivel, vector < int > &nma, vector < vector < int > > &vecini, deque < int > &s, vector < vector < int > > &bic ){
    v[k] = 1;
    s.push_front(k);
    if( tata == -1 ){
        nivel[k] = 1;
    }
    else nivel[k] = nivel[tata] + 1;
    nma[k] = nivel[k];
    for( int i = 0; i < vecini[k].size(); i++ ){
        int x;
        x = vecini[k][i];
        if( x != tata ){
            if( v[x] == 1 ){
                if( nma[k] > nivel[x] ){
                    nma[k] = nivel[x];
                }
            }
            else{
                DFS(x, k, v, nivel, nma, vecini, s, bic);
                if( nma[k] > nma[x] ){
                    nma[k] = nma[x];
                }
                if( nivel[k] <= nma[x] ){
                    vector < int > conex;
                    while( s[0] != x ){
                        conex.push_back(s[0]);
                        s.pop_front();
                    }
                    conex.push_back(x);
                    s.pop_front();
                    conex.push_back(k);
                    bic.push_back(conex);
                }
            }
        }
    }
}

int main(){
    vector < int > v, nivel,nma;
    deque < int > s;
    int n, m;
    ifstream fin( "biconex.in" );
    ofstream fout( "biconex.out" );
    fin >> n >> m;
    vector < vector < int > > vecini, bic;
    for( int i = 0; i <= n; i++ ){
        vector < int > x;
        vecini.push_back(x);
    }
    for( int i = 0; i < m; i++ ){
        int intrare, iesire;
        fin >> intrare >> iesire;
        vecini[intrare].push_back(iesire);
        vecini[iesire].push_back(intrare);
    }
    for( int i = 0; i <= n; i++ ){
        nivel.push_back(0);
        nma.push_back(0);
        v.push_back(0);
    }
    DFS( 1, -1, v, nivel, nma, vecini, s, bic );
    fout << bic.size() << "\n";
    for( int i = 0; i < bic.size(); i++ ){
        for( int j = 0; j < bic[i].size(); j++ ){
            fout << bic[i][j] << " ";
        }
        fout << "\n";
    }
}