#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N = 2e5+5; 
ll n,m,idx,dfn[N],low[N];
struct E{
    int u,v;
}g[N];
vector<int> e[N],vec;
void tarjan(int u,int las){
    dfn[u] = low[u] = ++idx;
    int son = 0;
    for(int id:e[u]){
        if(id == las) continue;
        int v = g[id].u^g[id].v^u;
        if(!dfn[v]) {
            son++;
            tarjan(v,id);
            if(las && low[v]>=dfn[u]) vec.pb(u);
            low[u] = min(low[v],low[u]);
        }else{
            low[u] = min(low[u],dfn[v]);
        }
    }
    if(!las && son>=2) vec.pb(u);
}
int main(){
    cin.tie(0),cout.tie(0);
    ios::sync_with_stdio(0);
    cin >> n >> m;
    for(int i=1;i<=m;i++){
        cin >> g[i].u >> g[i].v;
        if(g[i].u == g[i].v) continue; 
        e[g[i].u].pb(i),e[g[i].v].pb(i);
    }
    for(int i=1;i<=n;i++) if(!dfn[i]) tarjan(i,0);
    sort(vec.begin(),vec.end()),vec.erase(unique(vec.begin(),vec.end()),vec.end());
    cout << vec.size() << '\n';
    for(int x:vec) cout << x << ' ';
    return 0;
}