#include <fstream>
#include <vector>
#include <algorithm>

#define maxn 100001
#define vint vector<int>::iterator

using namespace std;

ifstream fin ("biconex.in");
ofstream fout ("biconex.out");

int viz[maxn],st[maxn],lowlink[maxn],depth[maxn],t,n,m,a,b,nrb;
vector<int> G[maxn],CB[maxn];

void dfs (int x, int lvl)
{
    viz[x] = 1;
    lowlink[x] = lvl;
    depth[x] = lvl;
    st[++t] = x;

    for (vint it = G[x].begin(); it != G[x].end(); ++it)
    {
        if (!viz[*it])
        {
            dfs (*it,lvl+1);
            lowlink[x] = min (lowlink[x],lowlink[*it]);

            if (lowlink[*it] >= lvl)
            {
                ++nrb;
                while (st[t] != x)
                {
                    CB[nrb].push_back (st[t]);
                    --t;
                }
                CB[nrb].push_back (x);
            }
        }
        else
        {
            lowlink[x] = min (lowlink[x],depth[*it]);
        }
    }
}

int main()
{
    fin>>n>>m;

    for (int i=1; i<=m; ++i)
    {
        fin>>a>>b;

        G[a].push_back (b);
        G[b].push_back (a);
    }

    for (int i=1; i <=n; ++i)
    {
        if (!viz[i])
        dfs (i,1);
    }

    fout<<nrb<<"\n";

    for (int i=1; i<=nrb; ++i)
    {
        for (vint it = CB[i].begin(); it != CB[i].end(); ++it)
          fout<<*it<<" ";
        fout<<"\n";
    }
}