1 /*by SilverN*/
 2 #include<iostream>
 3 #include<algorithm>
 4 #include<cstring>
 5 #include<cstdio>
 6 #include<cmath>
 7 #include<vector>
 8 using namespace std;
 9 const int mxn=20000;
10 const int mxm=120;
11 vector<int>e[mxn];
12 int gd[mxm];
13 int n;
14 int root,dtime=0;
15 int dfn[mxm],low[mxm];
16 int ans=0;
17 
18 void add_edge(int u,int v){
19     e[u].push_back(v);
20     e[v].push_back(u);
21     return;
22 }
23 void tarjan(int u){
24     int i;
25     int tot=0;
26     low[u]=dfn[u]=++dtime;
27     int v;
28     for(i=0;i<e[u].size();i++){
29         v=e[u][i];
30         if(!dfn[v]){
31             tarjan(v);
32             ++tot;
33             low[u]=min(low[v],low[u]);
34             if((u==root && tot>1)||(u!=root && low[v]>=dfn[u]))
35                 if(!gd[u]) gd[u]=true,ans++;
36         }
37         else low[u]=min(low[u],dfn[v]);
38     }
39     return;
40 }
41 int main(){
42     freopen("gd.in","r",stdin);
43     freopen("gd.out","w",stdout);
44     scanf("%d",&n);
45     int i,j;
46     int a,b;
47     while(scanf("%d%d",&a,&b)!=EOF)
48         add_edge(a,b);
49     for(i=1;i<=n;i++){
50         if(!dfn[i]){
51             root=i;
52             tarjan(i);
53         }
54     }
55     printf("%d\n",ans);
56     for(i=1;i<=n;i++){
57         if(gd[i])printf("%d\n",i);
58     }
59     return 0;
60 }