#include <set>
#include <map>
#include <list>
#include <queue>
#include <cmath>
#include <time.h>
#include <random>
#include <bitset>
#include <vector>
#include <cstdio>
#include <stdio.h>
#include <iomanip>
#include <assert.h>
#include <stdlib.h>
#include <memory.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <unordered_set>
#include <unordered_map>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define mk make_pair
#define fi first
#define se second

char buf[1 << 20],*p1,*p2;
inline char gc(){
	if (p1 == p2){
		p1 = buf;
		p2 = buf + fread(buf,1,1 << 20,stdin);
	}
	return p1 == p2 ? EOF : *p1++;
	// return getchar();
}

inline int read(){
	int t = 0,f = 1;
	register char c = gc();
	while (c < 48 || c > 57) f = (c == '-') ? (-1) : (f),c = gc();
	while (c >= 48 && c <= 57) t = (t << 1) + (t << 3) + (c ^ 48),c = gc();
	return f * t;
}

const int N = 2e4 + 3,M = 1e5 + 3;
int n,m,etot = 1,dfncnt,head[N],dfn[N],low[N];

struct Edge{
	int u,v,nxt;
}e[M << 1];

inline void adde(int u,int v) {e[++etot] = (Edge){u,v,head[u]},head[u] = etot;}

vector <int> ans;

void Tarjan(int u,int f){
	dfn[u] = low[u] = ++dfncnt;int child = 0;bool flag = 0;
	for (int i = head[u];i;i = e[i].nxt){
		int v = e[i].v;
		if (v == f) continue;
		if (!dfn[v]) Tarjan(v,i),low[u] = min(low[u],low[v]),++child;
		else low[u] = min(low[u],dfn[v]);
		if (low[v] >= dfn[u]) flag = 1;
	}
	if ((f && flag) || (!f && child > 1)) ans.emplace_back(u);
}

int main(){
#ifndef ONLINE_JUDGE
	freopen("in.in","r",stdin);
	// freopen("out.out","w",stdout);
#endif
	n = read(),m = read();
	for (int i = 1;i <= m;i++){
		int u = read(),v = read();
		adde(u,v),adde(v,u);
	}
	for (int i = 1;i <= n;i++) if (!dfn[i]) Tarjan(i,0);
	sort(ans.begin(),ans.end());
	printf("%d\n",(int)ans.size());
	for (int p : ans) printf("%d ",p);puts("");
	return 0;
}