#include <fstream>
using namespace std;

ofstream g ("biconex.out");
const int MAXN = 100005;
int n, m, niv[MAXN], minniv[MAXN], st[MAXN * 2], vf, nr, cnt;

struct nod
{
    int x;
    nod *leg;
};
nod *v[MAXN * 2], *c[MAXN * 2];

void add (nod *&dest, int vf)
{
    nod *p;
    p = new nod;
    p -> x = vf;
    p -> leg = dest;
    dest = p;
}

void citire()
{
    ifstream f ("biconex.in");
    f >> n >> m;
    int i, x, y;
    for (i = 1; i <= m; i++)
    {
        f >> x >> y;
        add (v[x], y);
        add (v[y], x);
    }
    f.close();
}

void tarjan (int x, int y)
{
    //niv[x] = nivelul lui x in arborele de cautare
    //minniv[x] = nivelul minim la care se poate ajunge din x
    niv[x] = minniv[x] = nr;
    nr++;
    st[++vf] = x;
    nod *p;
    for (p = v[x]; p != NULL; p = p -> leg)
    {
        if (y == p->x) continue;
        if (niv[p->x] == -1)
        {
            int in = vf;
            tarjan (p->x, x);
            minniv[x] = min (minniv[x], minniv[p->x]);
            if (minniv[p->x] >= niv[x])
            {
                cnt++;
                while (in != vf)
                    add (c[cnt], st[vf--]);
                add (c[cnt], x);
            }
        }
        else
            minniv[x] = min (minniv[x], niv[p->x]);
    }
}

int main()
{
    citire();
    for (int i = 1; i <= n; i++) niv[i] = -1;
    nr = vf = 0;
    for (int i = 1; i <= n; i++)
        if (niv[i] == -1)
            tarjan (i, 0);

    g << cnt << '\n';
    for (int i = 1; i <= cnt; i++)
    {
        for (nod *p = c[i]; p != NULL; p = p->leg)
            g << p->x << ' ';
        g << '\n';
    }
    return 0;
}