#if defined(LOCAL)
#define _GLIBCXX_DEBUG
#else
#define NDEBUG
#endif

#include <bits/stdc++.h>

#if defined(LOCAL)
#define DBG_MACRO_NO_WARNING
#include <dbg.hpp>
#else
#define dbg(x...) (0)
#endif

using namespace std;

using ll = long long;

// #define int ll
#define rep(i, f, t) for (int i = (f), ed##i = (t); i <= ed##i; ++i)
#define re(i, t) rep (i, 1, t)
#define per(i, t, f) for (int i = (t), ed##i = (f); i >= ed##i; --i)
#define ste(i, f, t, s) for (int i = (f), ed##i = (t); i <= ed##i; i += s)
#define nxt(i, f, g) for (int i = g.h[f]; i; i = g.e[i].n)
#define umod(x) ((x) >= mo && ((x) -= mo))
#define dmod(x) ((x) < 0 && ((x) += mo))
#define y1 y1__
#define fio(x) (freopen(x ".in", "r", stdin), freopen(x ".out", "w", stdout))

template <class T, class E>
__attribute__((always_inline)) inline void up(T &x, E &&y) {
  if (x < y) x = y;
}
template <class T, class E>
__attribute__((always_inline)) inline void down(T &x, E &&y) {
  if (y < x) x = y;
}

const int N = 1e6 + 9;
struct G {
  int tot = 1, h[N];
  struct E {
    int t, n;
  } e[N << 1];
  inline void Add(int f, int t) { e[++tot] = {t, h[f]}, h[f] = tot; }
} g;

int n, m, dfn[N], low[N], tim;
bool cut[N];

inline void Tar(int f, int eid) {
  dfn[f] = low[f] = ++tim;
  int son = 0;
  nxt (i, f, g) {
    if ((i >> 1) == eid) continue;
    int t = g.e[i].t;
    if (!dfn[i]) {
      ++son;
      Tar(t, i >> 1);
      if (eid && low[t] > dfn[f]) cut[f] = 1;
      down(low[f], low[t]);
    } else {
      down(low[f], dfn[t]);
    }
  }
  if (!eid && son >= 2) cut[f] = 1;
  // dbg(f, dfn[f], low[f]);
}

signed main() {
  ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
  cin >> n >> m;
  re (i, m) {
    int f, t;
    cin >> f >> t;
    g.Add(f, t), g.Add(t, f);
  }
  re (i, n)
    if (!dfn[i]) Tar(i, 0);
  int cnt = 0;
  re (i, n)
    if (cut[i]) ++cnt;
  cout << cnt << '\n';
  re (i, n)
    if (cut[i]) cout << i << ' ';
  cout << '\n';
  return 0;
}