#include <bits/stdc++.h>
#define pb push_back
#define Nmax 200005

using namespace std;

vector <int> L[Nmax],Comp[Nmax];
int lvl[Nmax],Low[Nmax],st[Nmax],top,nr_comp,n;
bool seen[Nmax];

void dfs(int nod, int tata)
{
    st[++top]=nod; seen[nod]=1;
    Low[nod]=lvl[nod];
    for(auto it : L[nod])
    {
        if(it==tata) continue;
        if(seen[it]) Low[nod]=min(Low[nod],lvl[it]);
        else
        {
            lvl[it]=lvl[nod]+1;
            dfs(it,nod);
            Low[nod]=min(Low[nod],Low[it]);
            if(Low[it]>=lvl[nod])
            {
                ++nr_comp;
                while(top && st[top]!=it)
                    Comp[nr_comp].pb(st[top--]);
                Comp[nr_comp].pb(st[top--]);
                Comp[nr_comp].pb(nod);
            }
        }
    }
}

int main()
{
    int m,x,y,i;
    ifstream cin("biconex.in");
    ofstream cout("biconex.out");
    cin>>n>>m;
    while(m--)
    {
        cin>>x>>y;
        L[x].pb(y); L[y].pb(x);
    }

    for(i=1;i<=n;++i)
        if(!seen[i]) dfs(i,0);

    cout<<nr_comp<<"\n";
    for(i=1;i<=nr_comp;++i)
    {
        for(auto it : Comp[i]) cout<<it<<" ";
        cout<<"\n";
    }
    return 0;
}