#include <bits/stdc++.h>

using namespace std;

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

const int nmax = 100005;
int n, m, z, id[nmax], low[nmax];
vector <int> G[nmax];
stack <pair <int, int> > stiva;
vector <vector <int> > ans;

void biconex(int a, int b){
    vector <int> aux;
    while (stiva.top().first != a && stiva.top().second != b){
        aux.push_back(stiva.top().second);
        stiva.pop();
    }
    aux.push_back(b);
    aux.push_back(a);
    stiva.pop();
    ans.push_back(aux);
}

void dfs(int nod){
    id[nod] = ++z;
    low[nod] = z;
    for (auto it : G[nod]){
        if (id[it] == 0){
            stiva.push({nod, it});
            dfs(it);
            low[nod] = min(low[nod], low[it]);
            if (low[it] >= id[nod]){
                biconex(nod, it);
            }
        }
        else{
            low[nod] = min(low[nod], id[it]);
        }
    }
}

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

    }
    fin.close();
    fout.close();
    return 0;
}