#include <bits/stdc++.h>
 using namespace std;

 ;
 ;
 int n, m;
 int ans;//个数 

  * MAXM], nxt[ * MAXM];
 void add(int x, int y) {
     nxt[++cnt] = head[x];
     head[x] = cnt;
     v[cnt] = y;
 }

 int dfn[MAXN], low[MAXN], ind;
 int cut[MAXN];

 void tarjan(int now, int fa) {
     dfn[now] = low[now] = ++ind;
     ;
     for (int i = head[now]; i ; i = nxt[i]) {
         if(!dfn[v[i]]) {
             tarjan(v[i], now);
             low[now] = min(low[now], low[v[i]]);

             ;//不为根节点
             if(now == fa) child++; //为根节点，子树统计
         }
         else {
             low[now] = min(low[now], dfn[v[i]]);
         }
     }
     ) cut[now] = ;//为根节点且有两个及以上的子节点
 }
 int main() {

     scanf("%d%d", &n, &m);
     ; i <= m; i++) {
         int x, y;
         scanf("%d%d", &x, &y);
         add(x, y);
         add(y, x);
     }

     ; i <= n; i++)
         if(!dfn[i])
             tarjan(i, i);

     ; i <= n; i++)
         )
             ans++;
     printf("%d\n", ans);
     ; i <= n; i++)
         )
             printf("%d ", i);

     ;
 }