#include <vector>
#include <fstream>
#include <stack>
#include <algorithm>
using namespace std;

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

vector<int> gr[100100];
int lv[100100], MIN[100100];
bool visited[100100];
int cont;
vector<vector<int>> ans;
stack<int> s;

void dfs(int nod) {
    lv[nod] = MIN[nod] = ++lv[0];
    s.push(nod);
    visited[nod] = true;

    for (int vec : gr[nod]) {
        if (!lv[vec]) {
            dfs(vec);
            MIN[nod] = min(MIN[nod], MIN[vec]);

            if (MIN[vec] >= lv[nod]) {
                vector<int> comp;
                while (true) {
                    int u = s.top(); s.pop();
                    comp.push_back(u);
                    if (u == vec) break;
                }
                comp.push_back(nod);
                ans.push_back(comp);
            }
        } else if (visited[vec]) {
            MIN[nod] = min(MIN[nod], lv[vec]);
        }
    }
    visited[nod] = false;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n, m;
    cin >> n >> m;

    for (int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        gr[a].push_back(b);
        gr[b].push_back(a);
    }

    for (int i = 1; i <= n; i++) {
        if (!lv[i]) {
            dfs(i);
        }
    }

    cout << ans.size() << '\n';
    for (auto& comp : ans) {
        sort(comp.begin(), comp.end());
        for (int x : comp) {
            cout << x << ' ';
        }
        cout << '\n';
    }

    return 0;
}