#include<map>
#include<set>
#include<queue>
#include<deque>
#include<cmath>
#include<ctime>
#include<bitset>
#include<vector>
#include<cstdio>
#include<string>
#include<random>
#include<cassert>
#include<cstdlib>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<unordered_map>
using namespace std;
using ll=long long;
using uint=unsigned int;
using ull=unsigned long long;
#define endl '\n'
#define lb lower_bound
#define ub upper_bound
#define eb emplace_back
#define fs fflush(stdout)
#define ump unordered_map
#define pq priority_queue
#define clz __builtin_clz
#define ctz __builtin_ctz
#define sz(x) (int)x.size()
#define np next_permutation
#define clzl __builtin_clzll
#define ctzl __builtin_ctzll
#define ppc __builtin_popcount
#define all(x) x.begin(),x.end()
#define ppcl __builtin_popcountll
#define fpi(x) freopen(x,"r",stdin)
#define fpo(x) freopen(x,"w",stdout)
#define uid uniform_int_distribution
#define urd uniform_real_distribution
#define me(x,y) memset(x,y,sizeof(x))
#define dbg(x) cerr<<"In Line "<<__LINE__<<' '<<#x<<'='<<(x)<<'\n'
#define gc p1==p2&&(p2=(p1=buf)+fread(buf,1,iosiz,stdin),p1==p2)?EOF:*p1++
#define iosiz 1024
char buf[iosiz],*p1=buf,*p2=buf;
template<class T> inline T &re(T &x){
	x=0;int f=1;char ch=gc;
	while(ch<48||ch>57){
		if(ch==45) f=-f;ch=gc;
	}
	while(ch>47&&ch<58) x=(x<<1)+(x<<3)+(ch^48),ch=gc;
	return x*=f;
}
#define mod 998244353
#define inf 0x3f3f3f3f
int ans,dep,dfn[20005],low[20005],tim;
bool cut[20005],vis[20005];
struct node{
    int to,num;
};
vector<node> edge[20005];
void dfs(int u){
    dfn[u]=low[u]=++tim,dep++;
    int cnt=0;
    for(auto v:edge[u]) if(!vis[v.num]){
        vis[v.num]=1;
        if(!dfn[v.to]){
            dfs(v.to),low[u]=min(low[u],low[v.to]);
            cut[u]|=dep^1&&low[v.to]>=dfn[u],cnt++;
        }
        else low[u]=min(low[u],dfn[v.to]);
    }
    cut[u]|=dep--==1&&cnt>1;
}
int main(){
    #ifdef CCPSDCGK
    fpi("shuju.txt");
    #endif
    int n=re(n),m=re(m);
    for(int i=1;i<=m;i++){
        int u=re(u),v=re(v);
        edge[u].eb((node){v,i}),edge[v].eb((node){u,i});
    }
    for(int i=1;i<=n;i++) if(!dfn[i]) dfs(i);
    for(int i=1;i<=n;i++) ans+=cut[i];
    cout<<ans<<endl;
    for(int i=1;i<=n;i++) if(cut[i]) cout<<i<<' ';
    return 0;
}