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

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

int n, m, timp;
vector<int> g[100001], st;
vector<vector<int>> comp;
int niv[100001], low[100001];

void dfs(int u, int tata) {
    niv[u] = low[u] = ++timp;
    st.push_back(u);
    for (int v : g[u]) {
        if (v == tata) continue;
        if (niv[v]) {
            low[u] = min(low[u], niv[v]);
        } else {
            dfs(v, u);
            low[u] = min(low[u], low[v]);
            if (low[v] >= niv[u]) {
                vector<int> c;
                int x;
                do {
                    x = st.back();
                    st.pop_back();
                    c.push_back(x);
                } while (x != v);
                c.push_back(u);
                comp.push_back(c);
            }
        }
    }
}

int main() {
    fin >> n >> m;
    for (int i = 0; i < m; i++) {
        int x, y;
        fin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    for (int i = 1; i <= n; i++)
        if (!niv[i]) dfs(i, 0);
    fout << comp.size() << "\n";
    for (auto& c : comp) {
        for (int x : c) fout << x << " ";
        fout << "\n";
    }
    return 0;
}