#include <vector>
#include <bitset>
#include <stack>
#include <fstream>
#include <algorithm>

using namespace std;

const int NMAX = 100005;
int N, M;
vector <int> graph[NMAX];
bitset <NMAX> seen;
int low[NMAX], h[NMAX];
stack <int> st;
vector < vector <int> > answer;

void dfs(int node, int father)
{
    low[node] = h[node] = h[father] + 1;
    seen[node] = 1;
    st.push(node);
    for (auto& son : graph[node])
    {
        if (son == father)
            continue;
        if (seen[son] == 1)
        {
            ///backedge
            low[node] = min(low[node], h[son]);
            continue;
        }
        dfs(son, node);
        low[node] = min(low[node], low[son]);
        if (low[son] >= h[node])
        {
            vector <int> bic;
            int x;
            do
            {
                x = st.top();
                st.pop();
                bic.push_back(x);
            } while (x != son);
            bic.push_back(node);
            answer.push_back(bic);
        }
    }
}

int main()
{
    ifstream fin("biconex.in");
    ofstream fout("biconex.out");
    fin >> N >> M;
    for (int i = 1; i <= M; ++i)
    {
        int u, v;
        fin >> u >> v;
        graph[u].push_back(v);
        graph[v].push_back(u);
    }
    for (int i = 1; i <= N; ++i)
        if (seen[i] == 0)
            dfs(i, 0);
    fout << answer.size() << "\n";
    for (auto& i : answer)
    {
        for (auto& j : i)
            fout << j << " ";
        fout << "\n";
    }
    fin.close();
    fout.close();
    return 0;
}