#include <fstream>
#include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,m;
const int N=1e5+5;
vector<int>a[N],st;
vector<vector<int>>conex;
int niv[N],up[N];
void dfs(int nod,int tt)
{
    niv[nod]=niv[tt]+1;
    up[nod]=niv[nod];
    st.push_back(nod);
    for(auto x: a[nod])
        if(x!=tt)
        {
            if(niv[x]!=0)
                up[nod]=min(up[nod],niv[x]);
            else
            {
                dfs(x,nod);
                up[nod]=min(up[nod],up[x]);
                if(niv[nod]<=up[x])
                {
                    vector<int>comp;

                    while(st.back()!=x)
                    {
                        comp.push_back(st.back());
                        st.pop_back();
                    }
                    comp.push_back(nod);
                    comp.push_back(x);
                    st.pop_back();
                    conex.push_back(comp);
                }
            }
        }
}
int main()
{
    f>>n>>m;
    int X,Y;
    for(int i=1;i<=m;i++)
    {
        f>>X>>Y;
        a[X].push_back(Y);
        a[Y].push_back(X);
    }
    for(int i=1;i<=n;i++)
        if(!niv[i])
            dfs(i,0);
    g<<conex.size()<<'\n';
    for(auto x: conex)
    {
        for(auto y: x)
            g<<y<<" ";
        g<<'\n';
    }
    return 0;
}