#include<fstream>
#include<vector>
#define nmax 200001
using namespace std;

int i,j,n,m,niv[nmax],c[nmax],viz[nmax],r1[nmax],r2[nmax],x,y,cr=0,nr=0;
vector<int> a[nmax];
vector<int> sol[nmax];
void add(int a,int b){
	
	int x,y;
	nr++;
	do
	{
		x=r1[cr];
		y=r2[cr--];
		sol[nr].push_back(y);
	}while(x!=a||y!=b);
	sol[nr].push_back(x);
}
void dfs(int nod,int tata){
	
	int x,i;
	niv[nod]=niv[tata]+1;
	c[nod]=niv[nod];
	viz[nod]=1;
	for(i=0;i<a[nod].size();++i){
		
		x=a[nod][i];
		if(!viz[x]){
			
			r1[++cr]=nod;
			r2[cr]=x;
			dfs(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(){
	
	freopen("biconex.in","r",stdin);
	freopen("biconex.out","w",stdout);
	scanf("%d%d",&n,&m);
	for(i=1;i<=m;i++){
		
		scanf("%d%d",&x,&y);
		a[x].push_back(y);
		a[y].push_back(x);
	}
	dfs(1,0);
	printf("%d\n",nr);
	for(i=1;i<=nr;i++){
		
		for(j=0;j<sol[i].size();++j)
			printf("%d ",sol[i][j]);
		printf("\n");
	}
	
	
	return 0;
}