#include <fstream>
#include <bitset>
#include <vector>
#define Nmax 1009

using namespace std;
ifstream f("dfs.in");
ofstream g("dfs.out");

vector <int> cc[Nmax];
bitset <Nmax> viz;
int n,m,x,y,sol,G[Nmax][Nmax];

void DFS(int node, vector<int>& v)
{
    viz[node]=1;
    v.push_back(node);
    for (int it=1; it<=n; ++it)
        if (G[node][it] && !viz[it])
        {
            DFS(it,v);
        }
}


int main()
{
    f>>n>>m;
    for (int i=1; i<=m; ++i)
    {
        f>>x>>y;
        G[x][y]=G[y][x]=1;
    }
    for (int i=1; i<=n; ++i)
        if(!viz[i])
        {
            ++sol;
            DFS(i,cc[sol]);
        }
    g<<sol<<'\n';
    for (int i=1; i<=sol; ++i)
    {
        for (vector <int>::iterator it=cc[i].begin(); it!=cc[i].end(); ++it)
            g<<*it<<' ';
        g<<'\n';
    }
    f.close();
    g.close();
}