#include <fstream>
#include <vector>

using namespace std;

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

vector<int> v[100010];

vector<vector<int> > comp;

vector<pair<int,int> > q;

int niv[100010],nivmin[100010];

char vaz[100010];

void compbiconex(int a,int b)
{
    vector<int> aux;
    int x,y;
    do
    {
        x=q.back().first;
        y=q.back().second;
        q.pop_back();
        aux.push_back(y);
    }while(a!=x || b!=y);
    aux.push_back(a);
    comp.push_back(aux);
}

void dfs(int nod,int lev)
{
    vaz[nod]=1;
    niv[nod]=nivmin[nod]=lev;
    for(vector<int>::iterator it=v[nod].begin();it!=v[nod].end();it++)
        if(!vaz[*it])
        {
            q.push_back({nod,*it});
            dfs(*it,lev+1);
            nivmin[nod]=min(nivmin[nod],nivmin[*it]);
            if(nivmin[*it]>=niv[nod]) compbiconex(nod,*it);
        }
        else nivmin[nod]=min(nivmin[nod],niv[*it]);
}

int main()
{

    int n,m,x,y;

    fin>>n>>m;

    for(int i=1;i<=m;i++)
    {
        fin>>x>>y;

        v[x].push_back(y);
        v[y].push_back(x);
    }
    for(int i=1;i<=n;i++)
        if(!vaz[i]) dfs(i,0);
    fout<<comp.size()<<"\n";
    for(int i=0;i<comp.size();i++)
    {
        for(int j=0;j<comp[i].size();j++) fout<<comp[i][j]<<" ";
        fout<<"\n";
    }
    return 0;
}