#include <bits/stdc++.h>

#define N 100005

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n, m;
vector<int> graf[N];
int dp[N], low[N];
stack<int> s;
vector<vector<int>> result;

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

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

  for(const auto& vecin : graf[node]) {
    if(dp[vecin]) {
      low[node] = min(low[node], dp[vecin]);
    } else {
      dfs(vecin, level + 1);
      low[node] = min(low[node], low[vecin]);

      if(low[vecin] >= dp[node]) {
        vector<int> res;
        res.push_back(node);
        int x;

        do {
          x = s.top();
          s.pop();
          res.push_back(x);
        } while(x != vecin);
        result.push_back(res);
      }
    }
  }
}

void solve() {
  dfs(1, 1);
  g<<result.size()<<'\n';
  for(const auto& comp : result) {
    for(const auto& element : comp) {
      g<<element<<" ";
    }
    g<<'\n';
  }
}

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