#include <fstream>
#include <bitset>
#include <vector>
#include <deque>

using namespace std;

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

int n, i, j, t[100001], low[100001], sol, m, x, y, nive[100001];
bitset<100001> f;
vector<int> v[100001], a[100001];
deque<pair<int, int> > stiva;

void dfs(int nod, int niv){
    low[nod] = niv;
    nive[nod] = niv;
    for(int i = 0;i<v[nod].size();i++){
        int vecin = v[nod][i];
        if(low[vecin] == 0){
            t[vecin] = nod;
            stiva.push_back(make_pair(nod, vecin));
            dfs(vecin, niv+1);
            low[nod] = min(low[nod], low[vecin]);
            if(low[vecin] >= niv){
                sol++;
                while(!stiva.empty() && stiva.back().first != nod){
                    a[sol].push_back(stiva.back().second);
                    stiva.pop_back();
                }
                stiva.pop_back();
                a[sol].push_back(vecin);
                a[sol].push_back(nod);
            }
        }
        else
            if(t[nod] != vecin)
                low[nod] = min(low[nod], nive[vecin]);
    }
}

int main(){
    fin>>n>>m;
    for(i=1;i<=m;i++){
        fin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, 1);
    fout<<sol<<"\n";
    for(i=1;i<=sol;i++){
        for(j = 0;j<a[i].size();j++)
            fout<<a[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}