#include <fstream>
#include <vector>
using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");
int n,m;
const int N=1e5+3;
vector<int>a[N];
int viz[N],nivel[N],up[N];
vector<int>que;
vector<vector<int>>componente;
void dfs(int nod,int tata)
{
    viz[nod]=1;
    nivel[nod]=nivel[tata]+1;
    up[nod]=nivel[nod];
    que.push_back(nod);
    for(auto it: a[nod])
        if(it!=tata)
        {
            if(viz[it])
                up[nod]=min(up[nod],nivel[it]);
            else
            {
                dfs(it,nod);
                up[nod]=min(up[nod],up[it]);
                if(up[it]>=nivel[nod])
                {
                    componente.push_back(vector<int>());
                    while(que.back()!=it)
                    {
                        componente[componente.size()-1].push_back(que.back());
                        que.pop_back();
                    }
                    que.pop_back();
                    componente[componente.size()-1].push_back(nod);
                    componente[componente.size()-1].push_back(it);
                }
            }
        }
}
int main()
{
    f>>n>>m;
    for(int i=1; i<=m; i++)
    {
        int X,Y;
        f>>X>>Y;
        a[X].push_back(Y);
        a[Y].push_back(X);
    }
    dfs(1,0);
    g<<componente.size()<<'\n';
    for(auto i : componente)
    {
        for(auto j: i)
            g<<j<<" ";
        g<<'\n';
    }
    return 0;
}