include

define N 100005

using namespace std;

int a,b;
int n,m;
int son;
int ans;
int root;
int col[N];
int dfn[N];
int low[N];
int col_num;
bool is_cut[N];

struct Edge{
int v,nxt;
}e[N<<2];
int head[N],tot;

void read(int &s){
char ch=getchar();
for(;!isdigit(ch);ch=getchar());
for(s=0;isdigit(ch);s=s*10+ch-'0',ch=getchar());
}

void add(int a,int b){
e[++tot].v=b;
e[tot].nxt=head[a];
head[a]=tot;
}

int tim_dfn;

void Tarjan(int x){
low[x]=dfn[x]=++tim_dfn;
for(int i=head[x];i;i=e[i].nxt){
int to=e[i].v;
if(!dfn[to]){
Tarjan(to);
if(x==root)son++;
else {
low[x]=min(low[x],low[to]);
if(low[to]>=dfn[x])is_cut[x]=true;
}
}
else
low[x]=min(low[x],dfn[to]);
}
}

int main(){
while(~scanf("%d%d",&n,&m)){
memset(is_cut,false,sizeof(is_cut));
memset(head,false,sizeof(head));
memset(dfn,false,sizeof(dfn));
memset(low,false,sizeof(low));
tim_dfn=tot=0;
for(int i=1;i<=m;++i){
read(a),read(b);
add(a,b);add(b,a);
}
ans=0;
for(int i=1;i<=n;++i)
if(!dfn[i]){
root=i,son=0;
Tarjan(i);
}
if(son>1)is_cut[root]=1;
for(int i=1;i<=n;++i)
if(is_cut[i])
ans++;
cout<<ans<<endl;
for(int i=1;i<=n;++i)
if(is_cut[i])
cout<<i<<' ';
}
return 0;
}