#include <fstream>
#include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,X,Y,m;
const int N=1e5+5;
vector<int>a[N],q;
vector<vector<int>>rez;
int niv[N],up[N];
bool viz[N];
void dfs(int nod,int tt)
{
    viz[nod]=true;
    niv[nod]=niv[tt]+1;
    up[nod]=niv[nod];
    q.push_back(nod);
    for(auto x : a[nod])
    {
        if(x==tt)
            continue;
        if(viz[x]==true)
            up[nod]=min(up[nod],niv[x]);
        else
        {
            dfs(x,nod);
            up[nod]=min(up[nod],up[x]);
            if(up[x]>=niv[nod])
            {
                vector<int>comp;
                comp.clear();
                while(q.back()!=x&&!q.empty())
                {
                    comp.push_back(q.back());
                    q.pop_back();
                }
                comp.push_back(x);
                comp.push_back(nod);
                rez.push_back(comp);
                q.pop_back();
            }
        }
    }
}
int main()
{
    f>>n>>m;
    for(int i=1;i<=m;i++)
    {
        f>>X>>Y;
        a[X].push_back(Y);
        a[Y].push_back(X);
    }
    dfs(1,0);
    g<<rez.size()<<'\n';
    for(auto x : rez)
    {
        for(auto y: x)
            g<<y<<" ";
        g<<'\n';
    }
    return 0;
}