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

using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");

const int NMAX = 100005;
int n, m;
vector<int> G[NMAX];
int niv[NMAX], low[NMAX];
vector<vector<int>> biconex;
bool viz[NMAX];
stack <int>stiva;
int tot;
vector<int>v;

void read()
{
	f >> n >> m;
	for (int i = 1; i <= m; i++)
	{
		int x, y;
		f >> x >> y;
		G[x].push_back(y);
		G[y].push_back(x);
	}
}

void dfs(int nod, int dad)
{
	viz[nod] = 1;
	niv[nod] = low[nod] = niv[dad] + 1;
	stiva.push(nod);
	for (auto it : G[nod])
	{
		if (!viz[it])
		{
			dfs(it, nod);

			low[nod] = min(low[nod], low[it]);
			if (low[it] >= niv[nod])
			{
				tot++;
				int curent;
				v.push_back(nod);
				do 
				{
					curent = stiva.top();
					v.push_back(curent);
					stiva.pop();
				} while (curent != it);
				biconex.push_back(v);
				v.clear();
			}
		}
		else {
			low[nod] = min(low[nod], niv[it]);
		}
	}
}

int main()
{
	read();
	dfs(1, 0);
	g << tot << '\n';
	for (int i = 0; i < tot; i++)
	{
		for (auto it : biconex[i])
		{
			g << it << ' ';
		}
		g << '\n';
	}
}