#include <bits/stdc++.h>

#define cin fin
#define cout fout

using namespace std;

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

int32_t main()
{
	cin.tie(nullptr)->sync_with_stdio(false);
	int n, m;
	cin >> n >> m;
	vector<vector<int>> g(n + 1);
	for (int i = 1; i <= m; ++i)
	{
		int u, v;
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	stack<pair<int, int>> s;
	vector<int> low(n + 1, INT_MAX);
	vector<int> depth(n + 1);
	vector<bool> viz(n + 1);
	vector<vector<pair<int, int>>> ans;
	function<void(int, int)> biconexe = [&](int node, int d)
	{
		depth[node] = d;
		viz[node] = true;
		for (auto i : g[node])
		{
			if (viz[i])
			{
				low[node] = min(low[node], depth[i]);
			}
			else
			{
				s.push({node, i});
				biconexe(i, d + 1);
				if (low[i] >= depth[node])
				{
					ans.push_back({});
					while (!s.empty())
					{
						pair<int, int> qui = s.top();
						ans.back().push_back(qui);
						s.pop();
						if (qui == pair<int, int>{node, i})
						{
							break;
						}
					}
				}
				low[node] = min(low[node], low[i]);
			}
		}
	};
	biconexe(1, 0);
	cout << (int)ans.size() << '\n';
	for (auto i : ans)
	{
		set<int> s;
		for (auto j : i)
		{
			s.insert(j.first);
			s.insert(j.second);
		}
		for (auto j : s)
		{
			cout << j << ' ';
		}
		cout << '\n';
	}
}