#include <bits/stdc++.h>

using namespace std;

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

int n, m, timp, biconex;
vector<int>G[100001], SOL[100001];
bool viz[100001];
int h[100001], low[100001], TT[100001];
stack<pair<int, int>>ST;

void DFS(int nod)
{
    viz[nod] = 1;
    h[nod] = low[nod] = ++timp;
    int children = 0;

    for(auto it: G[nod])
    {
        if(!viz[it])
        {
            ST.push(make_pair(nod, it));
            TT[it] = nod;
            ++children;
            DFS(it);
            low[nod] = min(low[nod], low[it]);

            if((low[it] >= h[nod]) || (children > 1))
            {
                ++biconex;
                int a, b;
                do
                {
                    a = ST.top().first;
                    b = ST.top().second;
                    ST.pop();
                    SOL[biconex].push_back(b);
                }while(a != nod && b != it);

                SOL[biconex].push_back(a);
            }
        }
        else if(it != TT[nod]) low[nod] = min(h[it], low[nod]);
    }
}

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

    //TT[1] = -1;
    DFS(1);

    fout << biconex << "\n";
    for(int i = 1; i <= biconex; ++i)
    {
        sort(SOL[i].begin(), SOL[i].end());
        for(auto it: SOL[i]) fout << it << " ";
        fout << "\n";
    }
    return 0;
}