#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 10, M = 4e6 + 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 dfn[N], low[N], ts, root;
set<int> _set;

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

    for (int i = h[u]; ~i; i = ne[i]) {
        int v = e[i];
        if (v == fa) continue;
        if (!dfn[v]) {
            son++; // 儿子数量在割点时有用
            dfs(v, u);
            low[u] = min(low[u], low[v]);
            // 记录割点
            if (u != root && low[v] >= dfn[u]) _set.insert(u);
            if (u == root && son >= 2) _set.insert(u);
        } else
            low[u] = min(low[u], dfn[v]);
    }
}
int n, m;

int main(void) {
    scanf("%d %d", &n, &m);
    // 链式前向星初始化
    memset(h, -1, sizeof h);
    while (m--) {
        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, -1);

    printf("%d\n", _set.size());

    for (auto i : _set) printf("%d ", i);
    return 0;
}