# include <bits/stdc++.h>

using namespace std;

const int N = 1e6 + 5;
int n , m;
int ecnt = 1 , head[N] , to[N] , nxt[N];
int ans , rt , DFN[N] , LOW[N] , Tcnt , cut[N];

void AddEdge(int u , int v) {nxt[++ecnt] = head[u] , head[u] = ecnt , to[ecnt] = v;}

void tarjan(int u , int fa)
{
    int cnt = 0;
    DFN[u] = LOW[u] = ++Tcnt;
    for(int i = head[u]; i; i = nxt[i])
    {
        int v = to[i];
        if(!DFN[v])
        {
            cnt++;
            tarjan(v , u);
            LOW[u] = min(LOW[u] , LOW[v]);
            if(u != rt && LOW[v] >= DFN[u]) cut[u] = 1;
        }
        LOW[u] = min(LOW[u] , LOW[v]);
    }
    // cout << u << ' ' << rt << ' ' << cnt << endl;
    if(!fa && cnt > 1) cut[u] = 1;
}

void Tarjan()
{
    for(int i = 1; i <= n; i++) if(!DFN[i])
        rt = i , tarjan(i , 0);
}

int main()
{
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> n >> m;
    for(int i = 1 , u , v; i <= m; i++) cin >> u >> v , AddEdge(u , v) , AddEdge(v , u);
    Tarjan();
    for(int i = 1; i <= n; i++) if(cut[i]) ans++;
    cout << ans << endl;
    for(int i = 1; i <= n; i++) if(cut[i]) cout << i << endl;
    return 0;
}