#include <iostream>
#include <fstream>
#include <vector>
#define NMAX 100000

using namespace std;

ifstream fin("biconex.in");
ofstream fout("biconex.out");

int n, m, vf, nrcb, nivel[NMAX+10], lowpoint[NMAX+10], viz[NMAX+10], stiva[NMAX+10];
vector <int> nod[NMAX+10], cb[NMAX+10];

void dfs(int x, int p)
{	nivel[x] = nivel[p] + 1;
	viz[x] = 1;
	lowpoint[x] = nivel[x];
	stiva[++vf] = x;
	for(auto u : nod[x])
		{	if(u == p) continue;
			if(!viz[u])
				{	dfs(u, x);
					if(lowpoint[u] >= nivel[x])
						{	nrcb++;
							while(stiva[vf] != u)
								{	cb[nrcb].push_back(stiva[vf]);
									vf--;
								}
							cb[nrcb].push_back(u);
							cb[nrcb].push_back(x);
							vf--;
						}
					lowpoint[x] = min(lowpoint[x], lowpoint[u]);
				}
			else
				lowpoint[x] = min(lowpoint[x], nivel[u]);
		}
}

int main()
{
	fin >> n >> m;
	for(int i=1; i<=m; i++)
		{	int nod1, nod2;
			fin >> nod1 >> nod2;
			nod[nod1].push_back(nod2);
			nod[nod2].push_back(nod1);
		}
	for(int i=1; i<=n; i++)
		if(!viz[i])
			dfs(i, 0);
	fout << nrcb << '\n';
	for(int i=1; i<=nrcb; i++)
		{	for(auto u : cb[i])
				fout << u << ' ';
			fout << '\n';
		}
	return 0;
}