#include <fstream>
#include <vector>
#define nmax 100000
#define mmax 200000
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,disc[nmax+5],low[nmax+5],timp=0,nrsol=0;
vector<int> v[nmax+5],sol;
vector < vector<int> > comp;
bool viz[nmax+5];
int minv(int x, int y)
{
    return x<y?x:y;
}
void dfs(int u, int parent)
{
    disc[u]=low[u]=disc[parent]+1;
    viz[u]=1;
    sol.push_back(u);
    for(int i : v[u])
        if(i!=parent)
        {
            if(viz[i])
                low[u] = minv(low[u], disc[i]);
            else
            {
                dfs(i,u);
                low[u] = minv(low[u], low[i]);
                if(low[i]>=disc[u])
                {
                    comp.emplace_back();
                    comp.back().push_back(u);
                    while(sol.back()!=i)
                    {
                        comp.back().push_back(sol.back());
                        sol.pop_back();
                    }
                    sol.pop_back();
                    comp.back().push_back(i);
                    ++nrsol;
                }
            }
        }
}
int main()
{
    fin>>n>>m;
    int x,y;
    for(int i=1;i<=m;i++)
        fin>>x>>y,v[x].push_back(y),v[y].push_back(x);
    dfs(1,0);
    fout<<nrsol<<"\n";
    for(auto &i : comp)
        {
            for(int j : i)
                fout<<j<<" ";
            fout<<"\n";
        }
    return 0;
}