#include <iostream>
#include <fstream>
#include <vector>
#include <stack>

using namespace std;
ifstream f("biconex.in");
ofstream g("biconex.out");

const int Nmax = 100005;
int n, m, Use[Nmax], Level[Nmax], Low[Nmax], nr;
vector <int> G[Nmax], sol[Nmax];
stack <int> S;

void DFS(int nod, int tata)
{
    Use[nod] = 1;
    Level[nod] = Low[nod] = Level[tata]+1;
    for(int i = 0; i < (int)G[nod].size(); i++)
    {
        int vecin = G[nod][i];
        if(tata == vecin) continue;
        if(!Use[vecin])
        {
            S.push(vecin);
            DFS(vecin, nod);
            Low[nod] = min(Low[nod], Low[vecin]);
            if(Low[vecin] >= Level[nod])
            {
                nr++;
                int c = S.top();
                while(c!=nod)
                {
                    S.pop();
                    sol[nr].push_back(c);
                    c = S.top();
                }
                sol[nr].push_back(nod);
            }
        }
        else Low[nod] = min(Low[nod], Level[vecin]);
    }
}

int main()
{
    f>>n>>m;
    while(m--)
    {
        int x,y;
        f>>x>>y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i = 1; i <= n; i++)
    {
        S.push(i);
        if(!Use[i]) DFS(i,0);
        S.pop();
    }
    g<<nr<<'\n';
    for(int i = 1; i <= nr; i++)
    {
        for(int j = 0; j < (int)sol[i].size(); j++)
            g<<sol[i][j]<<' ';
        g<<'\n';
    }
    return 0;
}