#include <bits/stdc++.h>

using namespace std;

ifstream f("componenteconexe.in");
ofstream g("componenteconexe.out");

int a[101][101], q[101], viz[101], p, u, n, m, contor;

void BFS(int start, int nrc)
{
    q[1] = start;
    viz[start] = nrc;
    p = u = 1;
    while(p <= u)
    {
        int x = q[p++];
        for(int i = 1; i <= n; i++)
            if(a[x][i] && viz[i] == 0)
        {
            q[++u] = i;
            viz[i] = nrc;
        }
    }

}

int main()
{
    int x, y, nrc = 0, i, j;
    f >> n;
    while(f >> x >> y)
    {
        a[x][y] = a[y][x] = 1;
    }

    for(i = 1; i <= n; i++)
    {
        if(viz[i] == 0)
        {
            nrc++;
            BFS(i,nrc);
        }
    }
    g << nrc << '\n';
    for(i = 1; i <= nrc; i++)
    {
        for(j = 1; j <= n; j++)
            if(viz[j] == i)
                g << j << ' ';
        g << '\n';
    }

    return 0;
}