#include <bits/stdc++.h>

using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
typedef pair<int,int> pii;
stack<pii> stiva;
int n,m;
vector<int> muchii[100005];
vector<vector<int>> sol;
int par[100005],niv[100005],nivmin[100005],use[100005];
void build(int a,int b)
{
	vector<int> v;
	while(!stiva.empty())
	{
		int x=stiva.top().first;
		int y=stiva.top().second;
		stiva.pop();
		v.push_back(x);
		v.push_back(y);
		if(x==a&&y==b)
			break;
		if(x==b&&y==a)
			break;
	}
	sort(v.begin(),v.end());
	v.erase(unique(v.begin(),v.end()),v.end());
	sol.push_back(v);
}
void dfs(int nod)
{
	use[nod]=1;
	nivmin[nod]=niv[nod];
	for(int i:muchii[nod])
	{
		if(i==par[nod])
			continue;
		if(!use[i])
		{
			par[i]=nod;
			niv[i]=niv[nod]+1;
			stiva.push({i,nod});
			dfs(i);
			nivmin[nod]=min(nivmin[nod],nivmin[i]);
			if(nivmin[i]>=niv[nod])
				build(i,nod);
		}
		else
			nivmin[nod]=min(nivmin[nod],niv[i]);
	}
}
int main()
{
	ios_base::sync_with_stdio(false);
	fin.tie(0);
	fin>>n>>m;
	for(int i=1;i<=m;i++)
	{
		int a,b;
		fin>>a>>b;
		muchii[a].push_back(b);
		muchii[b].push_back(a);
	}
	dfs(1);
	fout<<sol.size()<<'\n';
	for(auto i:sol)
	{	
		for(int j:i)
			fout<<j<<' ';
		fout<<'\n'; 
	}	
	return 0;
}