#include <fstream>
#include <vector>
#include <bitset>
#include <queue>
#include <algorithm>
#include <utility>
#include <set>

using namespace std;

ifstream cin("pamant.in");
ofstream cout("pamant.out");


const int MAXN = 100005;
const int oo = (1<<31)-1;

typedef vector<int> Graph[MAXN];
typedef vector<int> :: iterator It;

Graph G;
vector<int> Con;
set<int>ArtPoints;
int N, M;
vector<int> Dfn(MAXN, -1), Low(MAXN);
bitset<MAXN>Used;

inline void Get_min(int &a, int b){
    if(a>b)
        a=b;
}

inline void DFs(int Node, int Father, int actLevel){
    Dfn[Node] = Low[Node] = actLevel;
    int sons = 0;
    bool critical = false;
    for(It it = G[Node].begin(), fin = G[Node].end() ; it != fin ; ++ it)
        if(*it != Father){
            if(Dfn[*it] == -1){
                DFs(*it, Node, actLevel + 1);
                Get_min(Low[Node], Low[*it]);
                critical |= (Low[*it] >= Dfn[Node]);
                ++ sons;
            }
            else Get_min(Low[Node], Dfn[*it]);
        }
    if (Node != Father) {
        if (critical)
            ArtPoints.insert(Node);
    } else if (sons >= 2)
        ArtPoints.insert(Node);
}

int main(){
    cin >> N >> M;
    for(int i = 1 ; i <= M ; ++ i){
        int x, y;
        cin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    for(int i = 1 ; i <= N ; ++ i)
        if(Dfn[i] == -1 ){
            DFs(i, i, 1);
            Con.push_back(i);
        }
    cout << Con.size() << "\n";
    for(It it = Con.begin() , fin = Con.end() ; it != fin ; ++ it)
        cout << *it << " ";
    cout << "\n" << ArtPoints.size() <<"\n";
    for(set<int> :: iterator it = ArtPoints.begin() , fin = ArtPoints.end() ; it != fin ; ++ it)
        cout << *it << " ";
    cin.close();
    cout.close();
    return 0;
}