#include <fstream>
#include <vector>
#include <stack>
using namespace std;
ifstream in("biconex.in");
ofstream out("biconex.out");
int n,m,x,y,nr,niv[100010],nivmin[100010];
vector<vector<int>>a,r;
stack<int>s;
bool v[100010];
void arbore(int t,int n)
{
    v[n]=true;
    nivmin[n]=niv[n];
    s.push(n);
    for(auto x:a[n])
    {
        if(x==t)
            continue;
        if(v[x]==true)
        {
            nivmin[n]=min(nivmin[n],niv[x]);
            continue;
        }
        niv[x]=niv[n]+1;
        arbore(n,x);
        nivmin[n]=min(nivmin[n],nivmin[x]);
        if(nivmin[x]>=niv[n])
        {
            ++nr;
            while(!s.empty()&&s.top()!=x)
            {
                r[nr].push_back(s.top());
                s.pop();
            }
            r[nr].push_back(s.top());
            s.pop();
            r[nr].push_back(n);
        }
    }
    return;
}
int main()
{
    in>>n>>m;
    a.resize(n+5);
    r.resize(n+5);
    for(int i=1;i<=m;++i)
    {
        in>>x>>y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    arbore(0,1);
    out<<nr<<'\n';
    for(int i=1;i<=nr;++i)
    {
        for(auto x:r[i])
            out<<x<<' ';
        out<<'\n';
    }
    return 0;
}