#include <bits/stdc++.h>
#define LL long long
#define sl(n) strlen(n)
#define endline puts("")
#define pii pair<int , int>
#define pr_q priority_queue
#define debug puts("DEBUG.")
using namespace std;
const int N = 5e5 + 10;
const int inf = ~0u >> 2;
int n,m;
struct edge
{
	int v,w,nxt;
}e[N << 1];
int hd[N],cnt = 1;
void add(int u , int v)
{
	++cnt,e[cnt].v = v;
	e[cnt].nxt = hd[u],hd[u] = cnt;
}
vector<int> vc;
int dfn[N],dfn_t,low[N];
bool vis[N << 1];
void dfs(int u , int fa)
{
	// cout << u << endl;
	dfn[u] = low[u] = ++dfn_t;
	int son = 0;
	bool fl = 0;
	for(int i = hd[u];i;i = e[i].nxt)
	{
		if(vis[i] )
			continue;
		int v = e[i].v;
		if(dfn[v] )
			low[u] = min(low[u] , dfn[v] );
		else
		{
			++son;
			vis[i] = vis[i ^ 1] = 1;
			dfs(v , u);
			low[u] = min(low[u] , low[v] );
			fl |= low[v] >= dfn[u];
		}
	}
	if(!fa && son > 1)
		vc.push_back(u);
	else if(fa && fl && son >= 2)
		vc.push_back(u);
	// cout << u << " low= " << low[u] << " dfn= " << dfn[u] << endl;
}
int main()
{
	cin >> n >> m;
	for(int i = 1,u,v;i <= m;i++)
	{
		scanf("%d%d" , &u , &v);
		if(u == v)
			continue;
		add(u , v),add(v , u);
	}
	for(int i = 1;i <= n;i++)
		if( !dfn[i] )
			dfs(i , 0);
	sort( vc.begin() , vc.end() );
	cout << vc.size() << endl;
	for(int x : vc)
		printf("%d\n" , x);
	return 0;
}