2 0
 100000 0
 8 9
1 2
2 3
3 4
4 1
5 6
6 7
7 8
8 5
6 8
 2 1
1 2
 11 9
5 9
8 5
11 3
11 1
3 4
7 11
3 1
11 2
7 2
 7 9
7 3
7 4
1 2
2 3
3 1
3 4
4 5
5 6
6 4
 7 5
5 4
7 3
7 1
6 7
3 1
 7 8
1 2
2 3
3 4
4 1
3 5
5 6
6 7
7 3
 6 9
1 2
2 3
1 4
4 2
5 2
5 3
4 5
6 4
6 5
 7 9
1 2
2 4
4 3
3 1
2 3
4 5
5 6
6 7
7 4
 1 0
 6 7
1 2
2 3
3 1
3 4
4 5
5 6
6 4
 4 5
1 2
2 3
3 4
4 1
1 3
 100000 3
99998 99999
99999 100000
100000 99998

0

 0

 4
1 2 3 4 
 0

 6
3 4 6 7 8 9 
 9
1 2 3 4 5 6 7 8 9 
 3
2 3 5 
 8
1 2 3 4 5 6 7 8 
 0

 4
6 7 8 9 
 0

 6
1 2 3 5 6 7 
 0

 3
1 2 3 

#include <bits/stdc++.h>
using namespace std;
struct GraphSolver {
  vector<int> *graph;
  vector<bool> isCycle;
  vector<int> stack;
  vector<int> count;
  int n;
  GraphSolver(int n)
      : graph(new vector<int>[n]), isCycle(n, false), count(n, 0), n(n) {}
  void addEdge(int u, int v) { graph[u].push_back(v), graph[v].push_back(u); }
  bool dfs(int u, int parent) {
    bool res1 = false;
    stack.push_back(u);
    count[u] = 1;
    for (auto v : graph[u]) {
      if (v == parent) continue;
      if (count[v] > 0) {
        count[v]++;
        res1 = true;
        continue;
      }
      bool hasCycle = dfs(v, u);
      if (count[u] >= 2 || !hasCycle) {
        while (stack.back() != u) {
          if (count[u] == 2) isCycle[stack.back()] = true;
          stack.pop_back();
        }
        if (count[u] == 2) isCycle[u] = true;
        count[u] = 1;
      }
    }
    return res1;
  }
  vector<int> solve() {
    vector<int> res;
    dfs(0, -1);
    for (int i = 0; i < n; i++)
      if (isCycle[i]) res.push_back(i);
    return res;
  };
};
int main() {
  int n, m;
  scanf("%d %d\n", &n, &m);
  GraphSolver solver(n);
  int u, v;
  for (; m > 0; m--) {
    scanf("%d %d\n", &u, &v);
    solver.addEdge(u - 1, v - 1);
  }
  vector<int> res = solver.solve();
  printf("%d\n", res.size());
  for (auto v : res) printf("%d ", v + 1);
  printf("\n");
  return 0;
}
