#include<iostream>

 #include<cstdio>

 #include<cstring>

 #include<set>

 #include<stack>

 using namespace std;

 const int maxn=;

 const int maxm=;

 int n,m,cnt,dfn[maxn],low[maxn],times,p[maxn];

 bool iscut[maxn];

 struct edge{

     int u;

     int v;

     int next;

 }e[maxm];

 stack<edge> S;

 void insert(int u,int v){

     ++cnt;

     e[cnt].u=u;

     e[cnt].v=v;

     e[cnt].next=p[u];

     p[u]=cnt;

 }

 void dfs(int u,int fa){

     dfn[u]=low[u]=++times;

     int child=;

     for(int i=p[u];i!=-;i=e[i].next){

         int v=e[i].v;

         if(dfn[v]==){

             child++;

             dfs(v,u);

             low[u]=min(low[u],low[v]);

             if(low[v]>=dfn[u])iscut[u]=true;

         }

         else if(dfn[v]<dfn[u]&&v!=fa){

             low[u]=min(low[u],dfn[v]);

         }

     }

     if(fa==-&&child==) iscut[u]=false;

 }

 int main()

 {

     cin>>n>>m;

     memset(p,-,sizeof(p));

     memset(low,0x3f3f3f,sizeof(low));

     for(int i=;i<=m;i++){

         int x,y;

         scanf("%d%d",&x,&y);

         insert(x,y);

         insert(y,x);

     }

     for(int i=;i<=n;i++){

         if(!dfn[i]) dfs(i,-);

     }

     int ans=;

     for(int i=;i<=n;i++){

         if(iscut[i]) ans++;

     }

     cout<<ans<<endl;

     for(int i=;i<=n;i++){

         if(iscut[i]) cout<<i<<" ";

     }

     return ;

 }