#include <bits/stdc++.h>
#define Nmax 100005
#define pb push_back

using namespace std;

int n,lvl[Nmax],sus[Nmax],viz[Nmax],st[Nmax],top,nrComp;
vector <int> L[Nmax],Comp[Nmax];

inline void Dfs(int nod, int tata)
{
    viz[nod]=1; sus[nod]=lvl[nod];
    st[++top]=nod;
    for(auto it : L[nod])
    {
        if(it==tata) continue;
        if(viz[it]) sus[nod]=min(sus[nod],lvl[it]);
        else
        {
            lvl[it]=lvl[nod]+1;
            Dfs(it,nod);
            if(sus[it]>=lvl[nod])
            {
                ++nrComp;
                while(top && st[top]!=it) Comp[nrComp].pb(st[top--]);
                Comp[nrComp].pb(st[top--]);
                Comp[nrComp].pb(nod);
            }
            sus[nod]=min(sus[nod],sus[it]);
        }
    }
}

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