#include <fstream>
#include <vector>

using namespace std;

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

const int nmax = 100005;
vector <int> ls[nmax], sol[nmax];
int n, m, i, j, x, y, lmax[nmax], niv[nmax];
bool viz[nmax];
int stiva[nmax], vf, K;

void make_sol(int x, int tt) {
    sol[K].push_back(tt);
    while (vf > 0 && stiva[vf] != x) sol[K].push_back(stiva[vf--]);
    if (vf > 0) { sol[K].push_back(x); vf--;}
}

void dfs(int x, int tt) {
    int l = ls[x].size(), i, y;
    lmax[x] = niv[x] = niv[tt]+1;
    viz[x] = 1;
    for (i = 0; i < l; i++) {
        y = ls[x][i];
        if (viz[y]) {
            if (y != tt) lmax[x] = min(lmax[x], niv[y]);
        } else {
            stiva[++vf] = y;
            dfs(y,x);
            lmax[x] = min(lmax[x], lmax[y]);
            if (lmax[y] >= niv[x]) {
                K++;
                make_sol(y, x);
            }
        }
    }
}

int main() {
    f >> n >> m;
    while (m--) {
        f >> x >> y;
        ls[x].push_back(y);
        ls[y].push_back(x);
    }
    dfs(1, 0);
    g << K << '\n';
    for (i = 1; i <= K; i++) {
        for (vector<int>::iterator w = sol[i].begin(); w != sol[i].end(); w++)
            g << *w << ' ';
        g << '\n';
    }

    return 0;
}