#include<fstream>
#include<vector>
using namespace std;
int n,m,i,j,st1[200001],st2[200001],niv[200001],c[200001],nr,x,y,u;
vector<int>a[200001],sol[200001];
bool uz[200001];
void add(int a, int b)
{
	int x,y;
	nr++;
	do 
	{ 
		x=st1[u];
		y=st2[u--];
		sol[nr].push_back(y);
	}
	while(x!=a||y!=b);
	sol[nr].push_back(x);
}
void df(int nod,int tata)
{
	int i,x;
	niv[nod]=niv[tata]+1;
	c[nod]=niv[nod];
	uz[nod]=1;
	for(i=0;i<a[nod].size();++i)
	{
		x=a[nod][i];
		if(!uz[x])
		{
			st1[++u]=nod;
			st2[u]=x;
			df(x,nod);
			if(c[x]<c[nod])
				c[nod]=c[x];
			if(c[x]>=niv[nod])
				add(nod,x);
		}
		else 
			if(x!=tata&&c[x]<c[nod])
				c[nod]=c[x];
	}
}
int main()
{
	ifstream f("biconex.in");
	ofstream g("biconex.out");
	f>>n>>m;
	for(i=1;i<=m;++i)
	{
		f>>x>>y;
		a[x].push_back(y);
		a[y].push_back(x);
	}
	nr=u=0;
	df(1,0);
	g<<nr<<"\n";
	for(i=1;i<=nr;++i) 
	{
		for(j=0;j<sol[i].size();++j)
			g<<sol[i][j]<<" ";
		g<<"\n";
	}
	return 0;
}