#include<bits/stdc++.h>
using namespace std;
int n,m;
vector<int>a[100005];
int dfn[100005],low[100005],times,cnt[100005],sum;
void dfs(int u,int Root){
	int child=0;
	dfn[u]=low[u]=++times;
	for(int i=0;i<a[u].size();i++){
		int v=a[u][i];
		if(dfn[v]==0){
			child++;
			dfs(v,Root);
			low[u]=min(low[u],low[v]);
			if(low[v]>=dfn[u]&&u!=Root)cnt[u]=1;
		}else low[u]=min(low[u],dfn[v]);
	}
	if(u==Root&&child>1)cnt[u]=1;
}
int main(){
	cin>>n>>m;
	for(int i=1;i<=m;i++){
		int u,v;
		cin>>u>>v;
		a[u].push_back(v);
		a[v].push_back(u);
	}
	for(int i=1;i<=n;i++){
		if(!dfn[i])dfs(i,i);
	}
	for(int i=1;i<=n;i++){
		if(cnt[i])sum++;	
	}
	cout<<sum<<endl;
	for(int i=1;i<=n;i++){
		if(cnt[i])cout<<i<<' ';
	}
	return 0;
}