#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
int head[1000005],low[1000005],dfn[1000005],cut[1000005],n,m,cnt,time;
struct edge{
int v,next;
}e[1000005];
inline void add(int u,int v){
e[++cnt].v=v;
e[cnt].next=head[u];
head[u]=cnt;
}
inline void tarjan(int u,int fa){
low[u]=dfn[u]=++time;
int child=0;
for(int i=head[u];i!=-1;i=e[i].next){
int v=e[i].v;
if(!dfn[v]){
tarjan(v,fa);
low[u]=min(low[u],low[v]);
if(low[v]>=dfn[u]&&u!=fa)cut[u]=1;
if(u==fa)child++;
}
low[u]=min(low[u],dfn[v]);
}
if(child>=2&&u==fa)cut[u]=1;
}
int main(){
memset(head,-1,sizeof(head));
scanf("%d%d",&n,&m);
for(int i=1;i<=m;i++){
int x,y;
scanf("%d%d",&x,&y);
add(x,y);add(y,x);
}
for(int i=1;i<=n;i++)if(!dfn[i])tarjan(i,i);
int ans=0;
for(int i=1;i<=n;i++){
if(cut[i])ans++;
}
printf("%d\n",ans);
for(int i=1;i<=n;i++){
if(cut[i])printf("%d ",i);
}
}
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