#include <iostream>

#include <cstdio>

#include <algorithm>

#include <cstring>

using namespace std;

const int N=1e5+,M=1e5+,INF=1e9+;

inline int read(){

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

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

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

    return x;

}

int n=,m,u,v;

struct edge{

    int v,ne;

}e[M<<];

int h[N],cnt=;

inline void ins(int u,int v){

    cnt++;

    e[cnt].v=v;e[cnt].ne=h[u];h[u]=cnt;

    cnt++;

    e[cnt].v=u;e[cnt].ne=h[v];h[v]=cnt;

}

int dfn[N],low[N],dfc=,iscut[N];

void dfs(int u,int fa){

    dfn[u]=low[u]=++dfc;

    int child=;

    for(int i=h[u];i;i=e[i].ne){

        int v=e[i].v;

        if(!dfn[v]){

            child++;

            dfs(v,u);

            low[u]=min(low[u],low[v]);

            if(low[v]>=dfn[u]) iscut[u]=;

        }else if(dfn[v]<dfn[u]&&v!=fa) low[u]=min(low[u],dfn[v]);

    }

    if(fa==&&child==) iscut[u]=;

}

int main(){

    n=read();m=read();

    for(int i=;i<=m;i++){u=read();v=read();ins(u,v);}

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

    int ans=;

    for(int i=;i<=n;i++) if(iscut[i]) ans++;

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

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

}