#include<cstdio>
#include<vector>
#include<algorithm>
#include<cstring>
using namespace std;
vector<int> G[100005];
int n,m,i,x,y,timp,root,rootChildren,nrsol;
int low[100005],discover[100005];
bool articulation[100005];
vector<int> st;
vector<int> sol[100005];

void dfs(int x,int parent)
{
	timp++;
	low[x]=discover[x]=timp;
	st.push_back(x);
	for(int i=0;i<G[x].size();i++)
	{
		if(G[x][i]==parent) continue;
		if(discover[G[x][i]])
		{
			low[x]=min(low[x],discover[G[x][i]]);
		}
		else
		{
			if(x==root) rootChildren++;
			dfs(G[x][i],x);
			if(low[G[x][i]]>=discover[x])
			{
				nrsol++;
				int j=st.size()-1;
				while(st[j]!=x)
				{
					sol[nrsol].push_back(st[j]);
					j--;
					st.pop_back();
				}
				sol[nrsol].push_back(x);
			}
			if(low[G[x][i]]>=low[x])
			{
				articulation[x]=true;
			}
			low[x]=min(low[x],low[G[x][i]]);
		}
	}
	//st.pop_back();
}
int main()
{
	freopen("biconex.in","r",stdin);
	freopen("biconex.out","w",stdout);
	scanf("%d %d",&n,&m);
	for(int i=1;i<=m;i++)
	{
		scanf("%d %d",&x,&y);
		G[x].push_back(y);
		G[y].push_back(x);
	}
	for(int i=1;i<=n;i++)
	{
		if(discover[i]==0)
		{
			root=i;
			rootChildren=0;
			dfs(i,-1);
			if(rootChildren>=2)
				articulation[i]=true;
		}
	}
	printf("%d\n",nrsol);
	for(int i=1;i<=nrsol;i++)
	{
		for(int j=0;j<sol[i].size();j++)
			printf("%d ",sol[i][j]);
		printf("\n");
	}
	return 0;
}