#include <bits/stdc++.h>
#define MOD 1000000007
#define Nmax 100005
#define pb push_back
#define mp make_pair
#define INF 2000000000
#define eps 0.000000000001

using namespace std;

    ofstream fout("biconex.out");


int n,nr,cnt[Nmax],Low[Nmax],Niv[Nmax],St[Nmax],top;
long long sol;
bool viz[Nmax];
vector <int> L[Nmax],B[Nmax],Tree[Nmax];

inline void Dfs(int nod, int tata, int lvl)
{
    Niv[nod]=Low[nod]=lvl; viz[nod]=true; St[++top]=nod;
    for(auto it : L[nod])
    {
        if(it==tata) continue;
        if(viz[it]) Low[nod]=min(Low[nod],Niv[it]);
        else
        {
            Dfs(it,nod,lvl+1);
            Low[nod]=min(Low[nod],Low[it]);
            if(Low[it]>=Niv[nod])
            {
                ++nr;
                for(;top && St[top]!=it;B[nr].pb(St[top--]));
                B[nr].pb(St[top--]); B[nr].pb(nod);
            }
        }
    }
}

inline void Solve_Arbore()
{
    fout<<nr<<"\n";
    for(int i=1;i<=nr;++i)
    {
        for(auto it : B[i]) fout<<it<<" ";
        fout<<"\n";
    }
}

int main()
{
    int i,j,m,x,y;
    /*#ifndef ONLINE_JUDGE
        freopen ("date.in","r",stdin);
        freopen ("date.out","w",stdout);
    #endif*/
    //cin.sync_with_stdio(0);
        ifstream cin("biconex.in");

    cin>>n>>m;
    while(m--)
    {
        cin>>x>>y;
        L[x].pb(y); L[y].pb(x);
    }
    Dfs(1,0,1);
    Solve_Arbore();
    //cout<<sol;
    return 0;
}