#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#include <stack>

using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");
int n, m;
vector<int> graph[100001];
int dfn[100001], low[100001];
vector<vector<int>> result;
stack<int> s;

void read() {
  f>>n>>m;
  int x, y;
  for(int i = 1;i <= m;++i) {
    f>>x>>y;
    graph[x].push_back(y);
    graph[y].push_back(x);
  }
}

void dfs(const int& node, const int& level) {
  dfn[node] = low[node] = level;
  s.push(node);

  for(const auto& ngh : graph[node]) {
    if(dfn[ngh]) {
      low[node] = min(low[node], dfn[ngh]);
    } else {
      dfs(ngh, level + 1);
      low[node] = min(low[node], low[ngh]);

      if(low[ngh] >= dfn[node]) {
        vector<int> comp;
        comp.push_back(node);
        int x;

        do {
          x = s.top();
          s.pop();
          comp.push_back(x);
        } while(x != ngh);

        result.push_back(comp);
      }
    }
  }
}

void solve() {
  for(int i = 1;i <= n;++i) {
    if(!dfn[i]) {
      dfs(i, 1);
    }
  }

  g<<result.size()<<'\n';
  for(const auto& comp : result) {
    for(const auto& node : comp) {
      g<<node<<" ";
    }
    g<<'\n';
  }
}

int main() {
  read();
  solve();
  return 0;
}