#include <fstream>

using namespace std;
ifstream fin("graf.in");
ofstream fout("graf.out");
int n,viz[101],a[101][101],x,y,v[101],i,j,nr,nrcmp;
void citire()
{
    fin>>n;
    while(fin>>x>>y)
        a[x][y]=a[y][x]=1;
}
void DF(int k,int &nrcmp)
{
    viz[k]=1;
    v[k]=nrcmp;
    for(int i=1; i<=n; i++)
        if(!viz[i] && a[k][i]==1)
            DF(i,nrcmp);
}

int main()
{
    citire();
    nr=1;
    nrcmp=0;
    for(i=1;i<=n;i++)
        if(viz[i]==0)
        {
            nrcmp++;
            DF(i,nrcmp);

        }
    fout<<nrcmp<<endl;
    while(nr<=nrcmp)
    {for(i=1;i<=n;i++)
        if(v[i]==nr)
        fout<<i<<' ';
        fout<<endl;
        nr++;
    }
            return 0;
}