#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ull = unsigned long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
#define all(x) x.begin(),x.end()
constexpr int N = 2e4 + 10;
constexpr int M = 5e5 + 10;
constexpr ll Mod = 998244353;
constexpr int INF = 0x3f3f3f3f;
constexpr ll Base = 1277;
constexpr int MAXBIT = 30;
int root;
bool cut_point[N],bridge[M];;
struct EBCC {
    int n;
    vector<vector<pair<int,int>>> adj;
    vector<int> stk;
    vector<int> dfn,low,col;
    int cur,cnt,edgeid,points,edges;
    EBCC() {}
    EBCC(int n) {init(n);}
    void init(int n) {
        this->n=n;
        adj.assign(n+1,{});
        dfn.assign(n+1,-1);
        low.resize(n+1);
        col.assign(n+1,-1);
        stk.clear();
        cur=cnt=edgeid=points=edges=0;
    }
    void addEdge(int u,int v) {
        adj[u].push_back({v,edgeid++});
        adj[v].push_back({u,edgeid++});
    }
    void dfs(int x,int inedge) {
        int tot=0;
        dfn[x]=low[x]=cur++;
        stk.push_back(x);
        for(auto [y,id] : adj[x]) {
            if(id==(inedge^1)) continue;
            if(dfn[y]==-1) {
                dfs(y,id);
                ++tot;
                low[x]=min(low[x],low[y]);
                if(low[y]>dfn[x] && !bridge[id/2])
                {
                    edges+=1;
                    bridge[id/2]=1;
                }
                if(low[y]>dfn[x] && !cut_point[x])
                {
                    points+=1;
                    cut_point[x]=true;
                }
            }else if(col[y]==-1 && dfn[y]<dfn[x]) {
                low[x]=min(low[x],dfn[y]);
            }
        }
        if(x==root && tot<2 && cut_point[x])
        {
            points-=1;
            cut_point[x]=false;
        }
        if(dfn[x]==low[x]) {
            int y;
            cnt+=1;
            do{
                y=stk.back();
                col[y]=cnt;
                stk.pop_back();
            } while(y!=x);

        }
    }
    vector<int> work() {
        for(int i=1;i<=n;i++)
            if(dfn[i]==-1)
            {
                root=i;
                dfs(i,-1);
            }
        return col;
    }
    int ebccnum() {
        return cnt;
    }
    int cut_points() {
        return points;
    }
    int cut_edges() {
        return edges;
    }
};
void solve()
{
    int n,m;
    cin>>n>>m;
    EBCC ebcc(n);
    for(int i=1;i<=m;i++)
    {
        int u,v;
        cin>>u>>v;
        ebcc.addEdge(u,v);
    }
    ebcc.work();
    cout<<ebcc.cut_points()<<"\n";
    for(int i=1;i<=n;i++)
        if(cut_point[i])
            cout<<i<<"\n";
}
int main()
{
    ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    // #ifndef ONLINE_JUDGE
    // freopen("input.txt","r",stdin);
    // freopen("out.txt","w",stdout);
    // #endif
    int _ = 1;
    // cin >> _;
    while (_--)
        solve();
    return 0;
}