#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int n, m, t;
vector <vector <int>> G;
vector <int> enter;
vector <int> back;
vector <bool> visited;
vector <int> node;

void dfs(int u, int p = 0){
    visited[u] = true;
    enter[u] = back[u] = t++;
    int c = 1;
    for (int i = 0; i < G[u].size(); i++){
        int v = G[u][i];
        if (v == p){
            continue;
        }
        if (visited[v]){
            back[u] = min(back[u], enter[v]);
        } else {
            dfs(v, u);
            back[u] = min(back[u], back[v]);
            if ((back[v] >= enter[u]) && (p != 0)){
                node.push_back(u);
            }
            ++c;
        }
    }
    if ((p == 0) && (c > 2)){
        node.push_back(u);
    }
}

int main() {
    int dep, dest;
    cin >> n >> m;

    G.resize(n+1);
    back.resize(n+1);
    enter.resize(n+1);
    visited.resize(n+1);

    t = 0;

    for (int i = 1; i <= m; i++){
        cin >> dep >> dest;
        G[dep].push_back(dest);
        G[dest].push_back(dep);
    }

    for (int i = 0; i <= n; i++){
        visited[i] = false;
    }

    for (int i = 1; i <= n; i++){
        if (!visited[i]) {
            dfs(i);
        }
    }

    cout << node.size() << endl;

    sort(node.begin(), node.end());

    if (! node.empty()) {
        cout << node[0] << " ";
        for (int i = 1; i < node.size(); i++) {
            if (node[i-1] != node[i])
                cout << node[i] << " ";
        }
    }
    return 0;
}