#include<iostream>

 #include<cstdio>

 #include<cstdlib>

 #include<cstring>

 #include<cmath>

 #include<algorithm>

 #include<queue>

 #include<vector>

 #define ll long long

 #define inf 2139062143

 #define MAXN 100100

 using namespace std;

 inline int read()

 {

     int x=,f=;char ch=getchar();

     while(!isdigit(ch)) {if(ch=='-') f=-;ch=getchar();}

     while(isdigit(ch)) {x=x*+ch-'';ch=getchar();}

     return x*f;

 }

 int n,m,res,stp,cnt,fst[MAXN],to[MAXN<<],nxt[MAXN<<],dfn[MAXN],low[MAXN],ans[MAXN];

 void add(int u,int v) {nxt[++cnt]=fst[u],fst[u]=cnt,to[cnt]=v;}

 void tarjan(int x,int anc)

 {

     dfn[x]=low[x]=++stp;int rts=;

     for(int i=fst[x];i;i=nxt[i])

     {

         if(!dfn[to[i]])

         {

             tarjan(to[i],anc);

             low[x]=min(low[x],low[to[i]]);

             if(low[to[i]]>=dfn[x]&&x!=anc) ans[x]=;

             if(x==anc) rts++;

         }

         low[x]=min(low[x],dfn[to[i]]);

     }

     if(x==anc&&rts>) ans[anc]=;

 }

 int main()

 {

     n=read(),m=read();int a,b;

     for(int i=;i<=m;i++) {a=read(),b=read();add(a,b);add(b,a);}

     for(int i=;i<=n;i++) if(!dfn[i]) tarjan(i,i);

     for(int i=;i<=n;i++) if(ans[i]) res++;printf("%d\n",res);

     for(int i=;i<=n;i++) if(ans[i]) printf("%d ",i);

 }