#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
int n, m, dfx = 0, cnt = 0, hd[100010], e[1000010][2], dfn[100010], low[100010], ans[100010];
void dfs(int u, int fa){
	dfn[u] = ++dfx; low[u] = u;
	int i, v, x = 0;
	bool fl = false;
	for(i = hd[u]; i > 0; i = e[i][0]){
		v = e[i][1];
		if(dfn[v] == 0){
			dfs(v, u);
			x++;
			low[u] = min(low[u], low[v]);
			if(fa != 0 && low[v] >= dfn[u]) fl = true;
		}else if(v != fa) low[u] = min(low[u], dfn[v]);
	}
	if(fl) ans[++cnt] = u;
	if(fa == 0 && x > 1) ans[++cnt] = u;
}
int main()
{
	int i, u, v;
	scanf("%d%d", &n, &m);
	for(i = 1; i <= n; i++) hd[i] = 0, dfn[i] = 0;
	for(i = 2; i >> 1 <= m; i++){
		scanf("%d%d", &u, &v);
		e[i][0] = hd[u]; e[i][1] = v; hd[u] = i;
		i++;
		e[i][0] = hd[v]; e[i][1] = u; hd[v] = i;
	}
	for(i = 1; i <= n; i++){
		if(dfn[i] == 0) dfs(i, 0);
	}
	sort(ans + 1, ans + cnt + 1);
	printf("%d\n", cnt);
	for(i = 1; i <= cnt; i++) printf("%d ", ans[i]);
	return 0;
}