#include <bits/stdc++.h>

using namespace std;

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

const int kNmax = 1e5;

int n;
int m;
vector<int> adj[kNmax + 1];
vector<int> idx, low;
stack<int> stk;
vector <vector <int> > res;

int min(int a, int b)
{
	return a < b ? a : b;
}


void make_bicon_comp(int nod, int son)
{
	vector<int> curr_comp;
	int curr;

	do
    {
		curr = stk.top();
		stk.pop();
		curr_comp.push_back(curr);
	}
	while (curr != son);
	curr_comp.push_back(nod);
	res.push_back(curr_comp);
}

void cut_vertex(int nod, int parent, int time)
{
	idx[nod] = low[nod] = time;
	vector <int>::iterator it;
	for (it = adj[nod].begin(); it != adj[nod].end(); it++)
    {
		if (*it == parent)
		{
			continue;
		}
		if (idx[*it] == 0)
		{
			stk.push(*it);
			cut_vertex(*it, nod, time + 1);
			low[nod] = min(low[nod], low[*it]);

			if (low[*it] >= idx[nod])
			{
				make_bicon_comp(nod, *it);
			}
		}
        else
			low[nod] = min(low[nod], idx[*it]);
	}

}

void get_result()
{
	idx.resize(n + 1);
	low.resize(n + 1);
	idx.assign(n + 1, 0);

	cut_vertex(1, 0, 1);
}

int main()
{
	fin >> n >> m;
	for (int i = 1, x, y; i <= m; i++)
    {
		fin >> x >> y;
		adj[x].push_back(y);
		adj[y].push_back(x);
	}

	get_result();

	fout<< res.size() << '\n';
	for (int i = 0; i < res.size(); i++)
    {
		for (int nod : res[i])
			fout<< nod << ' ';
		fout<< '\n';
	}
}