#include <bits/stdc++.h>

using namespace std;
const int N = 2e4 + 10, M = 2e5 + 10;

//链式前向星
int e[M], h[N], idx, w[M], ne[M];
void add(int a, int b, int c = 0) {
    e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx++;
}

int n, m;                            // n个顶点,m条边
int dfn[N], low[N], timestamp, root; // tarjan算法
vector<int> v;                       //割点集合
//割点
void tarjan(int u) {
    low[u] = dfn[u] = ++timestamp;
    int son = 0;
    for (int i = h[u]; ~i; i = ne[i]) {
        int j = e[i];
        if (!dfn[j]) {
            son++;
            tarjan(j);
            low[u] = min(low[u], low[j]);
            //根据割点分析，low[j]>=dfn[u]的时候，u是割点
            //由于u可能有多个子节点，都会产生回边，u可能进入多次，后面需要去重
            if (u != root && low[j] >= dfn[u]) v.push_back(u);
        }
        low[u] = min(low[u], dfn[j]);
    }
    //特例：如果u是根，并且有两个以上的儿子节点，则u为割点
    if (u == root && son > 1) v.push_back(u);
}

int main() {
    scanf("%d %d", &n, &m);
    memset(h, -1, sizeof h);
    for (int i = 1; i <= m; i++) {
        int a, b;
        scanf("%d %d", &a, &b);
        add(a, b), add(b, a);
    }
    for (root = 1; root <= n; root++)
        if (!dfn[root]) tarjan(root);

    //排序+去重
    sort(v.begin(), v.end());
    v.erase(unique(v.begin(), v.end()), v.end());

    //输出割点个数
    printf("%d\n", v.size());
    //由小到大输出割点
    for (int i : v) printf("%d ", i);
    return 0;
}