#include <iostream>
#include <string>
#include <vector>
#include <algorithm>

using namespace std;

#define NM 100005
#define PB push_back

vector <int> G[NM], comp[NM];

int N, M, STACK[NM], viz[NM], nr_comp, NIV[NM], NIVB[NM];

void solve (int nod, int tata, int nivel)
{
	viz[nod] = 1;
	NIVB[nod] = NIV[nod] = nivel;
	
	for (int i = 0; i < G[nod].size(); ++i)
	{
		int nnod = G[nod][i];
		if (nnod == tata) continue;
		if (viz[nnod])
		{
			NIV[nod] = min(NIV[nod], NIVB[nnod]);
			continue;
		}	
		
		STACK[++STACK[0]] = nnod;
		solve(nnod, nod, nivel + 1);
		NIV[nod] = min(NIV[nod], NIV[nnod]);
		
		if (NIV[nnod] >= nivel)
		{
			++nr_comp;
			while (STACK[STACK[0]] != nnod) 
			{	
				comp[nr_comp].PB(STACK[STACK[0]]);
				--STACK[0];
			}	
			comp[nr_comp].PB(STACK[STACK[0]]);
			--STACK[0];
			comp[nr_comp].PB(nod);
		}	
	}	
}

int main()
{
	freopen ("biconex.in", "r", stdin);
	freopen ("biconex.out", "w", stdout);
	
	scanf ("%d %d", &N, &M);
	
	for (int i = 1; i <= M; ++i)
	{
		int a, b;
		scanf ("%d %d", &a, &b);
		
		G[a].PB(b);
		G[b].PB(a);
	}	
	
	G[0].PB(1);
	G[1].PB(0);
	
	STACK[++STACK[0]] = 0;
	STACK[++STACK[1]] = 1;
	
	solve (1, 0, 1);
	
	printf ("%d\n", nr_comp);
	
	for (int i = 1; i <= nr_comp; ++i)
	{
		for (int j = 0; j < comp[i].size(); ++j) printf ("%d ", comp[i][j]);
		printf ("\n");
	}	
	
	return 0;
}