#include<iostream>

#include<cstdio>

#include<cmath>

#include<cstring>

#include<algorithm>

#include<vector>

using namespace std;

#define LL long long

inline int read()

{

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

    while (ch<'' || ch>'') {if (ch=='-') f=-; ch=getchar();}

    while (ch>='' && ch<='') {x=x*+ch-''; ch=getchar();}

    return x*f;

}

#define MAXN 100010

int N,M,tot;

LL sum;

struct EdgeNode{int next,to,from;}edge[MAXN<<];

int head[MAXN],cnt=;

void AddEdge(int u,int v) {cnt++; edge[cnt].next=head[u]; head[u]=cnt; edge[cnt].to=v;}

void InsertEdge(int u,int v) {AddEdge(u,v); AddEdge(v,u);}

#define Pa pair<int,int>

vector<int>BCC[MAXN];

Pa st[MAXN]; int top;

int dfn[MAXN],low[MAXN],dfsn,cut[MAXN],bcc,belong[MAXN],d[MAXN];

void Tarjan(int now,int last)

{

    dfn[now]=low[now]=++dfsn; int son=;

    for (int i=head[now]; i; i=edge[i].next)

        if (!dfn[edge[i].to])

            {

                st[++top]=make_pair(now,edge[i].to);  son++;

                Tarjan(edge[i].to,now); low[now]=min(low[now],low[edge[i].to]);

                if (dfn[now]<=low[edge[i].to])

                    {

                        cut[now]=; bcc++; BCC[bcc].clear(); int tnow=-,tto=-;

                        while ()

                            {

                                tnow=st[top].first,tto=st[top].second; top--;

                                if (belong[tnow]!=bcc) BCC[bcc].push_back(tnow),belong[tnow]=bcc;

                                if (belong[tto]!=bcc) BCC[bcc].push_back(tto),belong[tto]=bcc;

                                if (tnow==now && tto==edge[i].to) break;

                            }

                    }

            }

        else if (dfn[edge[i].to]<dfn[now] && edge[i].to!=last)

            st[++top]=make_pair(now,edge[i].to),low[now]=min(low[now],dfn[edge[i].to]);

    if (last< && son==) cut[now]=;

}

int main()

{

    N=read(),M=read();

    for (int x,y,i=; i<=M; i++) x=read(),y=read(),InsertEdge(x,y),d[x]++,d[y]++;

    for (int i=; i<=N; i++) if (!dfn[i]) Tarjan(i,-);

    for (int i=; i<=N; i++) if (!cut[i] && d[i]==M-N+) tot++;

    printf("%d\n",tot);

    for (int i=; i<=N; i++) if (!cut[i] && d[i]==M-N+) printf("%d ",i); puts("");

    return ;

}