#include <iostream>
#include <vector>
#include <cstdio>
#include <cstdlib>
#include <fstream>
#include <cmath>
#include <algorithm>
#include <set>

using namespace std;

int n, m, timer;
bool color[200001], ans[200001];
vector <int> edge[200001];
int in_t[200001], ans_t[200001];

void dfs(int cur, int parent) {
	int ch = 0;
    color[cur] = true;
	timer++;
	in_t[cur] = timer;
	ans_t[cur] = timer;
    for (int i = 0; i < edge[cur].size(); i++) {
        int cur_t = edge[cur][i];
		if (cur_t == parent) {
			continue;
		}
        if (!color[cur_t]) {
			dfs(cur_t, cur);
			ans_t[cur] = min(ans_t[cur], ans_t[cur_t]);
			if (ans_t[cur_t] >= in_t[cur]) {
				ans[cur] = true;
			}
			ch++;
		} else {
			ans_t[cur] = min(ans_t[cur], in_t[cur_t]);
		}
    }
	if (parent == -1 && ch == 1) {
		ans[cur] = false;
	}
}

int main() {
    freopen ("points.in", "r", stdin);
    freopen ("points.out", "w", stdout);

	cin >> n >> m;

	for (int i = 0; i < m; i++) {
		int b, e;
		cin >> b >> e;
		b--;
		e--;
		edge[b].push_back(e);
		edge[e].push_back(b);
	}

	for (int i = 0; i < m; i++) {
		color[i] = false;
	}

	timer = 0;
	int cnt = 0;

	for (int i = 0; i <= n; i++) {
		if (!color[i]) {
			dfs(i, -1);
		}
	}
	for (int i = 0; i <= n; i++) {
		if (ans[i]) {
			cnt++;
		}
	}

	cout << cnt << endl;
	for (int i = 0; i <= cnt; i++) {
		if (ans[i]) {
			cout << i + 1 << endl;
		}
	}

    return 0;
}