#include <fstream>
#include <vector>
#include <algorithm>
#define Nmax 100099
using namespace std;
ifstream f("pamant.in");
ofstream g("pamant.out");

int N,M,T[Nmax],low[Nmax],found[Nmax],order,x,y;
vector < int > G[Nmax],CC,CV;

void ReadInput()
{
     f>>N>>M;
     for(int i=1;i<=M;++i)
          f>>x>>y , G[x].push_back(y) , G[y].push_back(x);
}



void DFS(int node)
{
     int children=0;
     low[node]=found[node]= ++order;
     for(vector<int>::iterator it=G[node].begin();it!=G[node].end();++it)
          if(!T[*it])
          {
               T[*it]=node; ++children;
               DFS(*it);
               low[node]=min(low[node],low[*it]);
               if(T[node]==node && children>1)CV.push_back(node);
               if(T[node]!=node && low[*it]>=found[node]) CV.push_back(node);

          }
          else if(*it!=T[node])low[node]=min(low[node],found[*it]);
}

void Tarjan()
{
     for(int i=1;i<=N;++i)T[i]=0;
     for(int i=1;i<=N;++i)
          if(!T[i])
          {
               T[i]=i,DFS(i);
               CC.push_back(i);
          }
}

template<class T>
void EliminateDuplicates(vector < T > &v)
{
     sort(v.begin(),v.end());
     v.erase(unique(v.begin(),v.end()) ,v.end());
}

void PrintOutput()
{
     g<<CC.size()<<'\n';
     for(vector<int>::iterator it=CC.begin();it!=CC.end();++it)
          g<<*it<<' ';
     g<<'\n';
     g<<CV.size()<<'\n';
     for(vector<int>::iterator it=CV.begin();it!=CV.end();++it)
          g<<*it<<' ';
     g<<'\n';
}

int main()
{
     ReadInput();
     Tarjan();
     EliminateDuplicates(CV);
     PrintOutput();
     f.close();g.close();
     return 0;
}