#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
#define nmax 100000
using namespace std;
ifstream fin("biconex.in");
ofstream fout("biconex.out");
int n,m,nr,disc[nmax+5],low[nmax+5];
bitset<nmax+5> viz;
vector<int> g[nmax+5],sol,comp[nmax+5];
int minv(int x,int y)
{
    return x<y?x:y;
}
void dfs(int nod, int father)
{
    disc[nod]=low[nod]=disc[father]+1;
    viz[nod]=1;
    sol.push_back(nod);
    for(int fiu : g[nod])
        if(fiu!=father)
        {
            if(viz[fiu])
                low[nod]=minv(low[nod],disc[fiu]);
            else
            {
                dfs(fiu,nod);
                low[nod]=minv(low[nod],low[fiu]);
                if(low[fiu]>=disc[nod])
                {
                    ++nr;
                    comp[nr].push_back(nod);
                    for(int i=sol.size()-1;sol[i]!=fiu;i--)
                        comp[nr].push_back(sol[i]),sol.pop_back();
                    comp[nr].push_back(fiu);
                    sol.pop_back();
                }
            }
        }
}
int main()
{
    fin>>n>>m;
    int x,y;
    for(int i=1;i<=m;i++)
    {
        fin>>x>>y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1,0);
    fout<<nr<<"\n";
    for(int i=1;i<=nr;i++)
    {for(int j=0;j<comp[i].size();j++)
        fout<<comp[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}