#include <bits/stdc++.h>
using namespace std;

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

int n, m;
vector<int> L[100005];
int niv[100005], low[100005];
bitset<100005> viz;
stack<int> st;
vector<set<int>> sol;

void DFS(int k, int ant)
{
    st.push(k);
    viz[k] = 1;
    low[k] = niv[k] = niv[ant] + 1;
    for (int i : L[k])
    {
        if (i == ant) continue;
        if (viz[i] == 1)
            low[k] = min(niv[i], low[k]);
        else
        {
            DFS(i, k);
            low[k] = min(low[k], low[i]);
            if (niv[k] <= low[i])
            {
                set<int> S;
                while (st.top() != i)
                {
                    S.insert(st.top());
                    st.pop();
                }
                S.insert(i); S.insert(k);
                sol.push_back(S);
                st.pop();
            }
        }
    }
}

int main()
{
    int i, j;
    fin >> n >> m;
    while (m--)
    {
        fin >> i >> j;
        L[i].push_back(j);
        L[j].push_back(i);
    }

    DFS(1, 0);

    fout << sol.size() << "\n";
    for (set<int> i : sol)
    {
        for (int j : i)
            fout << j << " ";
        fout << "\n";
    }
	return 0;
}