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

#define NMAX 100001

vector<vector<int>> graph = vector<vector<int>>(NMAX, vector<int>());

vector<vector<int>> biconex_components;

vector<int> low = vector<int>(NMAX);

vector<int> id = vector<int> (NMAX, -1);

stack<int> st;

ifstream fin("biconex.in");

ofstream fout("biconex.out");

int n, m;

int nr = 0;
int idx = 0;

void biconex(int node) {
    id.at(node) = low.at(node) = ++idx;
    st.push(node);

    for(auto& elem : graph.at(node)) {

        if(id.at(elem) != -1) {

            low.at(node) = min(id.at(elem), low.at(node));

            continue;

        }

        biconex(elem);

        low.at(node) = min(low.at(elem), low.at(node));
        if(low.at(elem) >= id.at(node)) {
            nr++;
            vector<int> biconex_component;
            int bc_node;

            do {
                bc_node = st.top();
                st.pop();
                biconex_component.push_back(bc_node);
            } while(bc_node != elem);
            biconex_component.push_back(node);
            biconex_components.push_back(biconex_component);
        }
    }
}

int main()
{
    fin >> n >> m;
    int x, y;
    for(int i = 1; i <= m; i++) {
        fin >> x >> y;
        graph.at(x).push_back(y);
        graph.at(y).push_back(x);
    }

    biconex(1);
    fout << nr << "\n";
    for(auto& bc : biconex_components) {
        for(auto& node : bc)
            fout << node << " ";
        fout << "\n";
    }
}