/*
  ! 以渺小启程，以伟大结束。
  ! Created: 2024/07/16 16:52:12
*/
#include <bits/stdc++.h>
using namespace std;

#define x first
#define y second
// #define int long long
#define mp(x, y) make_pair(x, y)
#define eb(...) emplace_back(__VA_ARGS__)
#define fro(i, x, y) for (int i = (x); i <= (y); i++)
#define pre(i, x, y) for (int i = (x); i >= (y); i--)
inline void JYFILE19();

typedef long long i64;
typedef pair<int, int> PII;

bool ST;
const int N = 1e6 + 10;
const int mod = 998244353;

int n, m, ct, u[N], v[N], head[N];
int dn[N], lw[N], vs[N];
struct edge {
  int to, nxt, val;
} e[N << 1];

inline void add(int x, int y, int z) {
  e[++ct] = {y, head[x], z}, head[x] = ct;
  e[++ct] = {x, head[y], z}, head[y] = ct;
}
inline void dfs(int x, int f) {
  dn[x] = lw[x] = ++ct; int son = 0;
  for (int i = head[x]; i; i = e[i].nxt) {
    if (e[i].to == f) continue;
    if (!dn[e[i].to]) {
      son++;
      dfs(e[i].to, x);
      lw[x] = min(lw[x], lw[e[i].to]);
      if (x != 1 && lw[e[i].to] >= dn[x]) vs[x] = 1;
    } else {
      lw[x] = min(lw[x], dn[e[i].to]);
      if (x != 1 && lw[e[i].to] >= dn[x]) vs[x] = 1;
    }
  }
  if (x == 1 && son >= 2) vs[x] = 1;
}

signed main() {
  JYFILE19();
  cin >> n >> m;
  fro(i, 1, m) {
    cin >> u[i] >> v[i];
    add(u[i], v[i], i);
  }
  ct = 0;
  fro(i, 1, n)
    if (dn[i] == 0) dfs(i, 0);
  ct = 0;
  fro(i, 1, n)
    if (vs[i] == 1) ct++;
  cout << ct << "\n";
  fro(i, 1, n)
    if (vs[i] == 1) cout << i << " ";
  cout << "\n";
  return 0;
}

bool ED;
inline void JYFILE19() {
  // freopen("", "r", stdin);
  // freopen("", "w", stdout);
  srand(random_device{}());
  ios::sync_with_stdio(0), cin.tie(0);
  double MIB = fabs((&ED-&ST)/1048576.), LIM = 512;
  cerr << "MEMORY: " << MIB << endl, assert(MIB<=LIM);
}