#include<fstream>
#include<vector>
#include<stack>

using namespace std;
ifstream in("biconex.in");
ofstream out("biconex.out");
const int N=100005;
int n,m,lvl[N],lowlink[N],cnt;
vector<int>a[N],sol[N];
stack<int>stiva;

void dfs(int x)
{
    int y;
	stiva.push(x);
	lowlink[x]=lvl[x];
	for(unsigned i=0;i<a[x].size();i++)
	{
	    y=a[x][i];
		if(lvl[y]!=0)
		{
			lowlink[x]=min(lowlink[x],lvl[y]);
			continue;
		}
		lvl[y]=lvl[x]+1;
		dfs(y);
		lowlink[x]=min(lowlink[x],lowlink[y]);
		if(lowlink[y]>=lvl[x])
		{
			cnt++;
			sol[cnt].push_back(x);
			int varf;
			do
			{
				varf=stiva.top();
				stiva.pop();
				sol[cnt].push_back(varf);
			}while(varf!=y);
		}
	}
}
int main()
{
	in>>n>>m;
	for(int x,y,i=1;i<=m;i++)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    lvl[1]=1;
	dfs(1);
	out<<cnt<<'\n';
	for(int i=1;i<=cnt;i++)
	{
		for(unsigned j=0;j<sol[i].size();j++)
			out<<sol[i][j]<<' ';
		out<<'\n';
	}
}