#include <fstream>
#include <vector>
#include <bitset>
#include <stack>
#define NMAX 100005

using namespace std;

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

bitset<NMAX> viz;
vector <int> ls[NMAX];
stack <int> stiva;
vector <vector <int> >sol;
int nv[NMAX], hmax[NMAX], n, i, j, x, y, m, ns;

void make_sol(int x, int tt) {
    int C;
    vector<int>tmp;
    tmp.push_back(tt);
    while (!stiva.empty() && stiva.top()!=x) {
        C=stiva.top();
        tmp.push_back(C);
        stiva.pop();
    }
    tmp.push_back(x);
    stiva.pop();
    sol.push_back(tmp);
}

void df(int x, int tt) {
    int i, l = ls[x].size(), y;
    hmax[x] = nv[x] = nv[tt]+1;
    viz[x]=1;
    for (i = 0; i < l; i++) {
        y = ls[x][i];
        if (y == tt)
            continue;
        if (viz[y] == 0) {
            stiva.push(y);
            df(y,x);
            hmax[x] = min(hmax[x], hmax[y]);
            if (hmax[y] >= nv[x]) {
                make_sol(y, x);
                ns++;
            }
        }
        else hmax[x] = min(hmax[x], nv[y]);
    }
}

int main() {
    f >> n >> m;
    nv[0]=-1;
    while (m--) {
        f >> x >> y;
        ls[x].push_back(y);
        ls[y].push_back(x);
    }
    for (i = 1; i <= n; i++)
        if (viz[i] == 0)
            df(i,0);

    vector <int>::iterator jj;
    g << ns <<'\n';
    for (i = 0; i < ns; i++) {
        for (jj=sol[i].begin(); jj!=sol[i].end(); jj++)
            g << *jj << ' ';
        g << '\n';
    }
    return 0;
}