#include<fstream>
#include<vector>

using namespace std;


ifstream fin("biconex.in");
ofstream fout("biconex.out");
int urca[100001],nivel[100001];
vector <int> lv[100005];
vector <int> com[100005];
bool viz[100005];
int nr;

int n,m;
vector <int> stack;
int cate,start;
void dfs(int nod,int niv,int tata)
{   int i;
    urca[nod]=niv;
    nivel[nod]=niv;
    stack.push_back(nod);
    int siz;
    siz=lv[nod].size();
    for(i=0;i<siz;i++)
    {
        int x=lv[nod][i];
        if(!nivel[x])
        {

            stack.push_back(nod);
            dfs(x,niv+1,nod);
            if(urca[nod]>urca[x])urca[nod]=urca[x];
               else
                   if(urca[x]>=niv)
                   {
                        int u,j;
                        u=stack.size()-1;

                        nr++;

                        while(stack[u]!=nod)
                        {
                            if(!viz[stack[u]])
                               {
                                   com[nr].push_back(stack[u]);
                                   viz[stack[u]]=1;
                                }
                            u--;
                            stack.pop_back();

                        }
                        if(!viz[stack[u]])com[nr].push_back(stack[u]);
                        stack.pop_back();

                        u=com[nr].size();
                        for(j=0;j<u;j++)
                            viz[com[nr][j]]=0;


                   }
        }
        else
            if(x!=tata&&nivel[x]<urca[nod]) urca[nod]=nivel[x];
    }
}






int main()
{
    int i;

    fin>>n;
    fin>>m;

    for(i=1;i<=m;i++)
    {
        int x,y;
        fin>>x>>y;
        lv[x].push_back(y);
        lv[y].push_back(x);
    }
    for(i=1;i<=n;i++)
        if(!nivel[i])dfs(i,1,0);

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

}