#include <bits/stdc++.h>
#define DEBUG(x) cerr << (#x) << ": " << (x) << '\n'

using namespace std;

void addBiconnectedComponent(int node, int sz, vector<int> &stk, 
  vector<vector<int>> &biconnected) {
  
  stk.emplace_back(node);
  biconnected.emplace_back();
  while ((int)stk.size() > sz) {
    biconnected.back().emplace_back(stk.back());
    stk.pop_back();
  }
}

void dfs(int node, int parent, vector<int> &depth, vector<int> &low, 
  vector<int> &stk, vector<vector<int>> &adj, vector<vector<int>> &biconnected) {
  
  stk.emplace_back(node);
  low[node] = depth[node];
  for (int &x : adj[node]) if (x != parent) {
    if (depth[x] == -1) {
      int sz = stk.size();
      depth[x] = depth[node] + 1;
      dfs(x, node, depth, low, stk, adj, biconnected);
      low[node] = min(low[node], low[x]);
      if (low[x] >= depth[node]) {
        addBiconnectedComponent(node, sz, stk, biconnected);
      }
    } else {
      low[node] = min(low[node], depth[x]);
    }
  }
}

int main() {
  freopen("biconex.in", "r", stdin);
  freopen("biconex.out", "w", stdout);
  ios::sync_with_stdio(0);
  cin.tie(0);

  int n, m; cin >> n >> m;
  vector<vector<int>> adj(n);
  for (int i = 0; i < m; ++i) {
    int u, v; cin >> u >> v;
    --u, --v;
    adj[u].emplace_back(v);
    adj[v].emplace_back(u);
  }
  vector<vector<int>> biconnected;
  vector<int> depth(n, -1), low(n);
  for (int i = 0; i < n; ++i) {
    if (depth[i] == -1) {
      vector<int> stk;
      depth[i] = 0;
      dfs(i, -1, depth, low, stk, adj, biconnected);
    }
  }
  cout << biconnected.size() << endl;
  for (auto &comp : biconnected) {
    for (int node : comp) {
      cout << node + 1 << ' ';
    }
    cout << '\n';
  }

#ifdef LOCAL_DEFINE
  cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
  return 0;
}