#include<cstdio>
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

#define maxn 100001

vector <int> graf[maxn] ;
vector <int> sol[maxn] ;

int n, m ;
int stiva[maxn] ;
int unde[maxn], level[maxn] ;
int sel[maxn] ;
int lgst, lgsol;

void adauga(int nod)
{
	++lgsol ;
	while( stiva[ lgst ] != nod )
	{
		sol[ lgsol ].push_back( stiva[ lgst ] ) ;
		--lgst ;
	}

	sol[ lgsol ].push_back( stiva[ lgst ] ) ;
	--lgst ;
}

void df(int nod, int tata)
{
	sel[nod] = true ;
	stiva[ ++lgst ] = nod ;

	level[nod] = level[tata] + 1 ;
	unde[nod] = level[nod] ;

	int aux = level[nod] ;

	for(size_t i = 0; i < graf[nod].size(); ++i )
	{
		int nod_act = graf[nod][i] ;
		if( sel[ nod_act ] )
			aux = min( aux, level[ nod_act ] ) ;
		else
		{
			df( nod_act, nod) ;
			unde[nod] = min( unde[nod], unde[ nod_act ] ) ;
			if( unde[ nod_act ] == level[nod] )
			{
				adauga( nod_act ) ;
				sol[ lgsol ].push_back(nod) ;
			}
		}
	}

	unde[nod] = min( unde[nod], aux ) ;
}

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 x, y ;
		scanf("%d%d", &x, &y);
		graf[y].push_back(x) ;
		graf[x].push_back(y) ;
	}

	df( 1, 0 );

	printf("%d\n", lgsol);

	for(int i = 1; i <= lgsol; ++i )
	{
		for(size_t j = 0; j < sol[i].size(); ++j )
			printf("%d ", sol[i][j]);
		printf("\n");
	}

	return 0 ;

}