#include <bits/stdc++.h>
#define nMax 100005

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

int n, m, x, y, t, k, biconex, low[nMax], ind[nMax], S[nMax];
vector<int> G[nMax], cx[nMax];

void dfs(int nod)
{
    low[nod]=t;
    ind[nod]=t;
    t++;
    S[++k]=nod;
    for(auto i:G[nod])
        if(ind[i]==0)
        {
          dfs(i);
          if(low[i]>=ind[nod])
          {
              biconex++;
              while(S[k]!=i)
              {
                  cx[biconex].push_back(S[k]);
                  k--;
              }
              cx[biconex].push_back(S[k]);
              k--;
              cx[biconex].push_back(nod);
          }
          low[nod]=min(low[i], low[nod]);
        }
        else
            low[nod]=min(low[nod], ind[i]);
}

int main()
{
    fin >> n >> m;
    while(m--)
    {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i=1; i<=n; i++)
        if(ind[i]==0)
        {
          t=0;
          k=0;
          dfs(i);
        }
    fout << biconex << "\n";
    for(int i=1; i<=biconex; i++)
    {
        for(auto j:cx[i])
            fout << j << " ";
        fout << "\n";
    }
    return 0;
}