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

using namespace std;

vector <int> L[Nmax],Comp[2*Nmax];
bool seen[Nmax];
int up[Nmax],lvl[Nmax],st[Nmax],top,nr_comp,n;

inline void dfs(int nod)
{
    seen[nod]=1; st[++top]=nod;
    up[nod]=lvl[nod];
    for(auto it : L[nod])
        if(seen[it]) up[nod]=min(up[nod],lvl[it]);
        else
        {
            lvl[it]=lvl[nod]+1;
            dfs(it);
            if(up[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);
            }
            up[nod]=min(up[nod],up[it]);
        }
}

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