#include<bits/stdc++.h>
#define int long long
#define lowbit(x) x&-x
#define lc (x<<1)
#define rc (x<<1|1)
using namespace std;
int n,m,rt,sum,idx;
const int N=2e4+5;
int dfn[N],low[N],ans[N];
vector<int> g[N];

void Tarjan(int x){
	dfn[x]=low[x]=++idx;
	int len=g[x].size();
	for(int i=0;i<len;i++){
		int y=g[x][i],son=0;
		if(!dfn[y]){
			Tarjan(y);
			low[x]=min(low[x],low[y]);
			if(low[y]>=dfn[x]){
				son++;
				if(son>1||x!=rt) ans[x]=1;
			}
		}
		else low[x]=min(low[x],dfn[y]);
	}
}
signed main()
{
	scanf("%lld%lld",&n,&m);
	for(int i=1;i<=m;i++){
		int a,b;scanf("%lld%lld",&a,&b);
		g[a].push_back(b);
		g[b].push_back(a);
	}
	for(int i=1;i<=n;i++) if(!dfn[i]) rt=i,Tarjan(i);
	for(int i=1;i<=n;i++) if(ans[i]) sum++;
	printf("%lld\n",sum);
	for(int i=1;i<=n;i++) if(ans[i]) printf("%lld ",i);
	return 0;
}