#include <bits/stdc++.h>
using namespace std;
const int N = 200005, M = N << 1;

//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 timestamp, root, cnt;
int low[N], dfn[N], cut[N];

void dfs(int u, int fa) {
    low[u] = dfn[u] = ++timestamp;
    int son = 0;

    for (int i = h[u]; ~i; i = ne[i]) {
        int j = e[i];
        if (j == fa) continue;
        if (!dfn[j]) {
            son++;
            dfs(j, u);
            low[u] = min(low[u], low[j]);
            if (u != root && low[j] >= dfn[u]) cut[u] = 1;
            if (u == root && son >= 2) cut[u] = 1; // child指的是dfs中生成树中的孩子
        }
        low[u] = min(low[u], dfn[j]);
    }
}
int n, m;
    int main(void) {
//文件输入输出
#ifndef ONLINE_JUDGE
    freopen("P3388.in", "r", stdin);
#endif

    scanf("%d %d", &n, &m);
    memset(h, -1, sizeof(h)); //链表的初始化
    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])
            dfs(root, root);

    for (int i = 1; i <= n; i++)
        if (cut[i]) cnt++;

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

    for (int i = 1; i <= n; i++)
        if (cut[i]) printf("%d ", i);
    return 0;
}