#include <fstream>
#include <vector>
#define Nmax 100002
using namespace std;

ifstream f("biconex.in");
ofstream g("biconex.out");

int n,m,NV[Nmax],x,y;
vector<int> v[Nmax],H;
vector<vector<int> > ans;

int dfs(int nod,int ant, int niv){
    int mn = niv;
    NV[nod] = niv;
    H.push_back(nod);
    for (auto it : v[nod]){
        if (it==ant) continue;
        if (NV[it]){
            mn = min(mn,NV[it]);
            continue;
        }
        mn = min(mn,dfs(it,nod,niv+1));
    }

    if (mn>=niv-1 && nod!=1){
        ans.push_back(*new vector<int>);
        while (!H.empty() && H.back()!=nod){
            ans.back().push_back(H.back());
            H.pop_back();
        }
        ans.back().push_back(H.back());
        H.pop_back();
        ans.back().push_back(H.back());
    }

    return mn;
}

int main()
{
    f>>n>>m;
    for (int i=1;i<=m;i++){
        f>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    dfs(1,-1,1);

    g<<ans.size()<<'\n';
    for (auto it : ans){
        for (auto it2 : it) g<<it2<<' ';
        g<<'\n';
    }

    return 0;
}