#include <bits/stdc++.h>
#define NMAX 100001
using namespace std;

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";
    }

}