#include <bits/stdc++.h>

using namespace std;

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

int n, m, f[100005], d[100005], step, biconex;
bool in_stack[100005];
vector <int> v[100005], ans[100005];
stack <int> st;

void Tarjan(int nod, int father)
{
    f[nod] = d[nod] = ++step;
    st.push(nod);
    in_stack[nod] = true;
    for(int i = 0; i < v[nod].size(); i++)
    {
        int child = v[nod][i];
        if(child == father) continue;
        if(!d[child]) Tarjan(child, nod);

        if(in_stack[child] == 0) continue;
        f[nod] = min(f[nod], f[child]);

        if(f[child] >= d[nod])
        {
            biconex++;
            while(!st.empty() && st.top() != nod)
            {
                ans[biconex].push_back(st.top());
                in_stack[st.top()] = false;
                st.pop();

            }
            ans[biconex].push_back(nod);


        }
    }

}
int main()
{
   fin >> n >> m;

   for(int i = 1; i <= m; i++)
   {
       int a, b;
       fin >> a >> b;
       v[a].push_back(b);
       v[b].push_back(a);
   }
    Tarjan(1, 0);
   fout << biconex << '\n';
   for(int i = 1; i <= biconex; i++)
   {
        for(int j = 0; j < ans[i].size(); j++)
            fout << ans[i][j] << " ";
        fout << '\n';
   }
    return 0;
}