#include <bits/stdc++.h>
#define mp make_pair
#define PII pair<int,int>
#define fi first
#define se second
#define pb push_back
#define show(x) cerr << #x << " = " << x << "\n";
using namespace std;

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

const int NMAX = 200005;

int n,m,nr,top,fat[NMAX],niv[NMAX],nivmin[NMAX];
vector<int>v[NMAX],t[NMAX],comp[NMAX];
int st[NMAX];
bitset<NMAX>viz;

void Dfs(int x)
{
	viz[x] = 1;
	niv[x] = niv[fat[x]] + 1;
	for (auto it : v[x])
		if (!viz[it])
		{
			fat[it] = x;
			t[x].pb(it);
			st[++top] = it; //node -> father
			Dfs(it);
			if (nivmin[it] >= niv[x])
			{
				nr++;
				while (st[top] != it) {comp[nr].pb(st[top]); top--;}
				comp[nr].pb(st[top]); top--;
			}
		}
    int mn = 1<<30;
    for (auto it : t[x]) mn = min(mn , nivmin[it]);
    for (auto it : v[x]) mn = min(mn , niv[it]);
    	
    nivmin[x] = mn;
}

int main()
{
	int i, x, y;

	fin >> n >> m;

	for (i = 1; i <= m; i++)
	{
		fin >> x >> y;
		v[x].pb(y);
		v[y].pb(x);
	}

	Dfs(1);
	for (i = 1; i <= n; i++) viz[i] = 0;
	fout << nr << "\n";
	for (i = 1; i <= nr; i++)
	{
		for (auto it : comp[i]) fout << it << " ";
		fout << fat[comp[i][comp[i].size() - 1]] << "\n"; 
	}
	
	return  0;
}