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

using namespace std;

const int NMAX = 100007;

vector < int > ans[NMAX];
vector < int > v[NMAX];
stack < pair < int, int > > Edge;
int viz[NMAX], Critic[NMAX], Level[NMAX];

int n, m;
int nr;

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

void add_ans(vector < int > &sol) {
    sort(sol.begin(), sol.end());
    sol.resize(unique(sol.begin(), sol.end()) - sol.begin());
}

void dfs(int node) {
    viz[node] = 1;
    Critic[node] = Level[node];
    for(vector < int > :: iterator it = v[node].begin(); it != v[node].end(); ++it) {
        if(viz[*it] == 0) {
            Level[*it] = Level[node] + 1;
            Edge.push(make_pair(node, *it));
            dfs(*it);
            Critic[node] = min(Critic[node], Critic[*it]);
            if(Critic[*it] >= Level[node]) {
                ++nr;
                while(Edge.top() != make_pair(node, *it)) {
                    ans[nr].push_back(Edge.top().first);
                    ans[nr].push_back(Edge.top().second);
                    Edge.pop();
                }
                ans[nr].push_back(Edge.top().first);
                ans[nr].push_back(Edge.top().second);
                Edge.pop();
                add_ans(ans[nr]);
            }
        }
        else {
            if(Level[*it] < Level[node] - 1) {
                Critic[node] = min(Critic[node], Level[*it]);
            }
        }
    }
}

int main() {
    cin >> n >> m;
    for(int i = 1; i <= m; ++i) {
        int a, b;
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1);
    cout << nr << "\n";
    for(int i = 1; i <= nr; ++i) {
        for(vector < int > :: iterator it = ans[i].begin(); it != ans[i].end(); ++it) {
            cout << *it << " ";
        }
        cout << "\n";
    }
}