#include <bits/stdc++.h>

using namespace std;

ifstream fi("biconex.in");
ofstream fo("biconex.out");
const int MAX_N = 100001;
vector <int> ad[MAX_N];
vector <vector<int>> sol;
stack <int> stk;
bool viz[MAX_N];
int lvl[MAX_N], low[MAX_N];

void dfs(int nod){
  viz[nod] = true;
  stk.push(nod);
  for(auto fiu : ad[nod]){
    if(!viz[fiu]){
      lvl[fiu] = lvl[nod] + 1;
      low[fiu] = lvl[nod] + 1;
      dfs(fiu);
      if(low[fiu] >= lvl[nod]){
        vector <int> v;
        while(stk.top() != fiu){
          v.push_back(stk.top());
          stk.pop();
        }
        stk.pop();
        v.push_back(fiu);
        v.push_back(nod);
        sol.push_back(v);
      }
      low[nod] = min(low[nod], low[fiu]);
    }
    else
      low[nod] = min(low[nod], lvl[fiu]);
  }
}

int main()
{
  int n, m, x, y;
  fi >> n >> m;
  for(int i = 0; i < m; i++){
    fi >> x >> y;
    ad[x].push_back(y);
    ad[y].push_back(x);
  }
  for(int i = 1; i <= n; i++)
    if(!viz[i])
      dfs(i);
  fo << sol.size() << '\n';
  for(auto v : sol){
    for(auto e : v)
      fo << e << ' ';
    fo << '\n';
  }
  fi.close();
  fo.close();
  return 0;
}