#include <fstream>
#define  N 101
using namespace std;
ifstream fin("componenteconexe.in");
ofstream fout("componenteconexe.out");
struct nod
{
    int info;
    nod*urm;
}*L[N];

int viz[N];

int n,m,nd;
void Citire()
{
    fin>>n;
    int x,y;
    nod*p;
    while(fin>>x>>y)
    {
        p=new nod;
        p->info=y;
        p->urm=L[x];
        L[x]=p;
        p=new nod;
        p->info=x;
        p->urm=L[y];
        L[y]=p; ///neorien
    }
}
void Sortare(int nd)
{
    int aux;
    for(nod*p=L[nd]; p->urm; p=p->urm)
        for(nod*q=p->urm; q; q=q->urm)
            if(p->info>q->info)
            {
                aux=p->info;
                p->info=q->info;
                q->info=aux;
            }
}
void DFS(int nd,int cc)
{
    nod*p;
    ///fout<<nd<<' ';
    p=L[nd];
    viz[nd]=cc;
    while(p)
    {
        if(viz[p->info]==0)
            DFS(p->info,cc);
        p=p->urm;
    }
}

int main()
{
    Citire();
    for(int i=1; i<=n; i++)
        Sortare(i);

    int cc=0;
    for(int i=1; i<=n; i++)
        if(viz[i]==0)
        {
            cc++;
            DFS(i,cc);
        }
    fout<<cc<<'\n';

    for(int j=1;j<=cc;j++)
    {
        for(int i=1;i<=n;i++)
            if(viz[i]==j)fout<<i<<' ';
        fout<<'\n';
    }
    return 0;
}