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

using namespace std;

long long inf = 1e9;

int n, m;
vector < vector < int > > g;
vector < bool > used;
vector < int > tin, f;
set <int> dots;
int timer = 0;

void dfs_find_points(int v, int par = -1) {
    used[v] = true;
    tin[v] = timer;
    timer++;
    f[v] = tin[v];

    int cntDfs = 0;

    for (int i = 0; i < g[v].size(); i++) {
        int to = g[v][i];
        if (to == par) {
            continue;
        }
        if (used[to])
            f[v] = min(f[v], tin[to]);
        else
        {
            dfs_find_points(to, v);
            cntDfs++;
            f[v] = min(f[v], f[to]);

            if (f[to] >= tin[v] && par != -1) {
                dots.insert(v);
            }
        }
    }

    if (par == -1 && cntDfs > 1) {
        dots.insert(v);
    }
}



int main() {
    cin >> n >> m;
    g.assign(n, vector <int>());
    used.assign(n, false);
    tin.assign(n, inf);
    f.assign(n, inf);

    for (int i = 0; i < m; i++) {
        int x, y;
        cin >> x >> y;
        x--;
        y--;
        g[x].push_back(y);
        g[y].push_back(x);
    }

    for (int i = 0; i < n; i++) {
        if (used[i] == false) {
            dfs_find_points(i, -1);
        }
    }

    cout << dots.size() << "\n";

    for (auto e : dots) {
        cout << e + 1 << "\n";
    }

    system("pause");
    return 0;
}