#include <bits/stdc++.h>

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
//-----------------------------------------------------------------
///Globale
int n,nivel[100001],rasp,nr;
vector<int>muchii[100001],raspuns[200001];
bitset<100001>ap;
pair<int,int>st[200001];
//-----------------------------------------------------------------
///Functii
void citire();
void rezolvare();
void afisare();
//-----------------------------------------------------------------
int main()
{
	citire();
	rezolvare();
	afisare();
	return 0;
}
//-----------------------------------------------------------------
void afisare()
{
	g << rasp << '\n';
	for(int i = 1; i <= rasp; ++i)
	{
		for(auto nod : raspuns[i])
			g << nod << " ";
		g << '\n';
	}
}
//-----------------------------------------------------------------
void dfs(int nod)
{
	bool ver = 0;
	int mi = n + 1;
	int par;
	for(auto vecin : muchii[nod])
		if(ap[vecin] == 0)
		{
			ver = 1;
			ap[vecin] = 1;
			nivel[vecin] = nivel[nod] + 1;
			st[++nr] = {nod,vecin};
			dfs(vecin);
		}
		else if(nivel[vecin] < mi)
		{
			mi = nivel[vecin];
			par = vecin;
		}
	if(nr && st[nr].second == nod)
	{
		rasp++;
		raspuns[rasp].push_back(nod);
		raspuns[rasp].push_back(par);
		while(nr > 0 && st[nr].first != par)
		{
			raspuns[rasp].push_back(st[nr].first);
			nr--;
		}
		if(nr)
            nr--;
	}
}
//-----------------------------------------------------------------
void rezolvare()
{
	for(int i = 1; i <= n; ++i)
		if(ap[i] == 0)
			if(muchii[i].size() == 0)
				continue;
			else
			{
				ap[i] = 1;
				nivel[i] = 1;
				nr = 0;
				dfs(i);
			}
}
//-----------------------------------------------------------------
void citire()
{
	int m;
	f >> n >> m;
	while(m--)
	{
		int a,b;
		f >> a >> b;
		muchii[a].push_back(b);
		muchii[b].push_back(a);
	}
	f.close();
}