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

using namespace std;

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

const int maxN = 100005;

int n, m, depth[maxN], max_sus[maxN];
vector <int> G[maxN];
vector <pair <int, int>> muchii;
vector <int> comp;
vector <vector <int>> bicomp;

void dfs(int nod, int sus)
{
    depth[nod] = depth[sus] + 1;
    max_sus[nod] = depth[nod];
    for(int vecin : G[nod])
    {
        if(vecin == sus)
            continue;
        if(depth[vecin] == 0)
        {
            muchii.push_back({nod, vecin});
            dfs(vecin, nod);
            max_sus[nod] = min(max_sus[nod], max_sus[vecin]);
            if(max_sus[vecin] >= depth[nod])
            {
                int x, y;
                do
                {
                    x = muchii.back().first, y = muchii.back().second;
                    muchii.pop_back();
                    comp.push_back(x), comp.push_back(y);
                }
                while(x != nod || y != vecin);
                sort(comp.begin(), comp.end());
                comp.erase(unique(comp.begin(), comp.end()), comp.end());
                bicomp.push_back(comp);
                comp.clear();
            }
        }
        else
            max_sus[nod] = min(max_sus[nod], depth[vecin]);
    }
}

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, 0);
    fout << bicomp.size() << '\n';
    for(auto c : bicomp)
    {
        for(int elem : c)
            fout << elem << ' ';
        fout << '\n';
    }
    return 0;
}