#include <fstream>
#include <vector>
#include <stack>
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");

#define NMAX 100001

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

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

stack<int> st;

int n, m;

int nr = 0;
int idx = 0;

void biconex(int node) {
    id[node] = low[node] = ++idx;
    st.push(node);
    for(auto& elem : graph.at(node)) {
        if(id.at(elem) != -1) {
            low[node] = min(id[elem], low[node]);
            continue;
        }
        biconex(elem);
        low[node] = min(low[elem], low[node]);
        if(low[elem] >= id[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);
            bc.push_back(biconex_component);
        }
    }
}

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

    biconex(1);
    fout << nr << "\n";
    for(int  i = 0; i < int(bc.size()); ++i) {
        for(int j = 0; j < int(bc[i].size()); ++j)
            fout << bc[i][j] << " ";
        fout << "\n";
    }
}