/*
  Lefter Sergiu - 06/04/2023
 */
#include <fstream>
#include <vector>
#include <stack>

using namespace std;

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

const int N = 1e5;

stack<int> stiva;
vector<vector<int>> cbc;
vector<int> a[N + 1];
int t_in[N + 1], t_min[N + 1], timp;

void adauga_cbc(int x, int y, vector<int> &c) {
    while (stiva.top() != y) {
        c.push_back(stiva.top());
        stiva.pop();
    }
    c.push_back(y);
    stiva.pop();
    c.push_back(x);
}

void DFS(int x, int t) {
    t_min[x] = t_in[x] = ++timp;
    stiva.push(x);
    for (auto y: a[x]) {
        if (y == t) {
            continue;
        }
        if (t_in[y] == 0) { //y e fiu al lui x in arborele DFS
            DFS(y, x);
            t_min[x] = min(t_min[x], t_min[y]);
            if (t_min[y] >= t_in[x]) {
                vector<int> c;
                adauga_cbc(x, y, c);
                cbc.push_back(c);
            }
        }
        else { //y este ascendent (dar nu tata) al lui x in arborele DFS
            t_min[x] = min(t_min[x], t_in[y]);
        }
    }
}

int main() {
    int n, m;
    in >> n >> m;
    for (int i = 0; i < m; i++) {
        int x, y;
        in >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    for (int i = 1; i <= n; i++) {
        if (t_in[i] == 0) {
            DFS(i, 0);
        }
    }
    out << cbc.size() << '\n';
    for (auto c: cbc) {
        for (auto x: c) {
            out << x << " ";
        }
        out << "\n";
    }
    in.close();
    out.close();
    return 0;
}