#include<bits/stdc++.h>
#define ll long long
using namespace std;
const ll N=2e4;
ll read(){
	ll S=0,F=1;char ch=getchar();
	while(!isdigit(ch)){
		if(ch=='-')F*=-1;
		ch=getchar();
	}while(isdigit(ch)){
		S=(S<<3)+(S<<1)+(ch^48);
		ch=getchar();
	}return S*F;
}ll n,m,u,v,dfn[N+10],low[N+10],cnt;
ll buc[N+10],ind[N+10];queue<ll >que;
vector<ll >to[N+10],vs;
void dfs(ll id,ll rt){
	low[id]=dfn[id]=++cnt;ll son=0,bk=0;
	for(ll i=0;i<to[id].size();i++){
		if(!dfn[to[id][i]]){
			dfs(to[id][i],id);son++;
			low[id]=min(low[id],low[to[id][i]]);
		}else low[id]=min(low[id],dfn[to[id][i]]);
		if(low[to[id][i]]>=dfn[id]&&!bk&&id!=rt)bk++,vs.push_back(id);
	}if(!bk&&rt==id&&son>1)vs.push_back(id);
	return;
}int main(){
	n=read();m=read();
	while(m--){
		u=read();v=read();
//		swap(u,v);
		to[u].push_back(v);to[v].push_back(u);
	}for(ll i=1;i<=n;i++)if(!dfn[i])dfs(i,i);
	sort(vs.begin(),vs.end());
	printf("%lld\n",vs.size());
	for(ll i=0;i<vs.size();i++)printf("%lld ",vs[i]);
	putchar('\n');return 0;
}