#include <fstream>
#include <vector>
#include <stack>

using namespace std;

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

stack <int> stv;
vector <int> ls[100005];
vector <vector <int> > sol;
bool viz[100005];
int n, m, x, y, i, ns;
int niv[100005], hmax[100005];

void write_sol(int x, int tt) {
    int C;
    vector <int> tmp;
    tmp.push_back(tt);
    //g << tmp.front() << ' ' << x << '\n';
    while (!stv.empty() && (C=stv.top())!=x) {
        tmp.push_back(C);
        stv.pop();
    }
    tmp.push_back(x);
    if (!stv.empty()) stv.pop();

    vector <int>::iterator j;
    /*for (j = tmp.begin(); j != tmp.end(); j++)
        g << *j << ' ';
    g << '\n';*/
    sol.push_back(tmp);
}

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

int main() {
    f >> n >> m;
    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 j;
    vector<vector<int> >::iterator I;
    g << ns << '\n';
    for (I = sol.begin(); I != sol.end(); I++) {
        for (j = I -> begin(); j != I -> end(); j++)
            g << *j <<' ';
        g << '\n';
    }
    return 0;
}