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

using namespace std;

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

const int maxN = 100005;
int n, m, depth[maxN], maxsus[maxN];
bool used[maxN];
vector <int> G[maxN], comp;
vector <vector <int>> bicomp;
vector <pair <int, int>> lista;

void dfs(int nod, int tata)
{
    used[nod] = 1;
    depth[nod] = depth[tata] + 1;
    maxsus[nod] = depth[nod];
    for(int vecin : G[nod])
    {
        if(vecin == tata)
            continue;
        if(used[vecin])
            maxsus[nod] = min(maxsus[nod], depth[vecin]);
        if(!used[vecin])
        {
            lista.push_back({nod, vecin});
            dfs(vecin, nod);
            maxsus[nod] = min(maxsus[nod], maxsus[vecin]);
            if(maxsus[vecin] >= depth[nod])
            {
                int x, y;
                do
                {
                    x = lista.back().first;
                    y = lista.back().second;
                    lista.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();
            }
        }
    }
}

int main()
{
    ios_base::sync_with_stdio(false);
    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;
}