#include <bits/stdc++.h>

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
vector<int> c,v[100010];
stack<int> St;
vector<vector<int> > C;
int n,m,i,x,y,niv[100010],up[100010];
void df(int nod,int tata);
int main()
{
    f>>n>>m;
    for(i=1;i<=m;i++)
    {
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!niv[i])
            df(i,0);
    g<<C.size()<<'\n';
    for(auto it:C)
    {
        for(auto that:it)
            g<<that<<' ';
        g<<'\n';
    }
    return 0;
}
void df(int nod,int tata)
{
    niv[nod]=up[nod]=niv[tata]+1;
    for(auto it:v[nod])
        if(it!=tata)
        {
            if(!niv[it])
            {
                St.push(it);
                df(it,nod);
                up[nod]=min(up[nod],up[it]);
                if(up[it]>=niv[nod])
                {
                    c.resize(0);
                    while(St.top()!=it)
                    {
                        c.push_back(St.top());
                        St.pop();
                    }
                    c.push_back(it);
                    c.push_back(nod);
                    St.pop();
                    C.push_back(c);
                }
            }
            else
                up[nod]=min(up[nod],niv[it]);
        }
}