// Include
#include <fstream>
#include <utility>
#include <vector>
#include <stack>
#include <set>
using namespace std;

// Definitii
#define pb push_back
#define mp make_pair

#define edge pair<int, int>

// Constante
const int sz = (int)1e5+1;

// Functii
void dfs(int node, int father, int level);
void biconex(edge stop);

// Variabile
ifstream in("biconex.in");
ofstream out("biconex.out");

int nodes, edges;

int minLevel[sz];

vector<int> graph[sz];
stack<edge> st;

vector< set<int> > answer;

// Main
int main()
{
	in >> nodes >> edges;
	
	int rFrom, rTo;
	while(edges--)
	{
		in >> rFrom >> rTo;
		
		graph[rFrom].pb(rTo);
		graph[rTo].pb(rFrom);
	}
	
	dfs(1, -1, 1);
	
	out << answer.size() << '\n';
	
	vector< set<int> >::iterator it, end=answer.end();
	for(it=answer.begin() ; it!=end ; ++it)
	{
		set<int>::iterator sit, send=it->end();
		for(sit=it->begin() ; sit!=send ; ++sit)
			out << *sit << ' ';
		
		out << '\n';
	}
	
	in.close();
	out.close();
	return 0;
}

void dfs(int node, int father, int level)
{
	minLevel[node] = level;
	
	vector<int>::iterator it, end=graph[node].end();
	for(it=graph[node].begin() ; it!=end ; ++it)
	{
		if(*it == father)
			continue;
		if(minLevel[*it])
		{
			minLevel[node] = min(minLevel[node], minLevel[*it]);
			continue;
		}
		st.push(mp(node, *it));
		dfs(*it, node, level+1);
		minLevel[node] = min(minLevel[node], minLevel[*it]);
		if(level <= minLevel[*it])
			biconex(mp(node, *it));
	}
}

void biconex(edge stop)
{
	edge current;
	set<int> answer;
	do
	{
		current = st.top();
		st.pop();
		answer.insert(current.first);
		answer.insert(current.second);
	} while(current != stop);
	
	::answer.pb(answer);
}