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

#define ll long long
using namespace std;

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

struct Nod { int level, returnLevel; vector<int> v; };

int nrC;

Nod node[100002];
stack<int> myStack;
vector<int> comp[100002];

void dfs(int nod, int level)
{
	node[nod].level = level;
	node[nod].returnLevel = level;
	myStack.push(nod);

	for (int i = 0; i < node[nod].v.size(); i++)
		if (node[node[nod].v[i]].level == 0)
		{
			dfs(node[nod].v[i], level + 1);

			if (node[node[nod].v[i]].returnLevel < level)
				node[nod].returnLevel = min(node[node[nod].v[i]].returnLevel, node[nod].returnLevel);
			else
			{
				nrC++;
				while (myStack.top() != node[nod].v[i])
				{
					comp[nrC].push_back(myStack.top());
					myStack.pop();
				}
				comp[nrC].push_back(node[nod].v[i]);
				myStack.pop();
				comp[nrC].push_back(nod);
			}
		}
		else
			if (node[node[nod].v[i]].level < node[nod].level - 1)
				node[nod].returnLevel = min(node[node[nod].v[i]].level, node[nod].returnLevel);
}

int main()
{
	int n, m, n1, n2;

	fin >> n >> m;
	for (int i = 1; i <= m; i++)
	{
		fin >> n1 >> n2;
		node[n1].v.push_back(n2);
		node[n2].v.push_back(n1);
	}

	dfs(1, 1);

	if (myStack.size() > 1)
	{
		nrC++;
		while (!myStack.empty())
		{
			comp[nrC].push_back(myStack.top());
			myStack.pop();
		}
	}

	fout << nrC << '\n';
	for (int i = 1; i <= nrC; i++)
	{
		for (int j = 0; j < comp[i].size(); j++)
			fout << comp[i][j] << ' ';
		fout << '\n';
	}
	return 0;
}