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;
const int N = 3e5 + 6;
int n, m, num[100005], ncyc = 0, cycIn[100005], result[100005], cnt = 0;
int dd[N], head[N];
vector<pair<int, int> > a[100005];
set<int> In[100005];
int re(int h, int k) {
  if (h == 0) return k;
  if (k == 0) return h;
  dd[h] = 1, dd[k] = 1;
  return (head[h] < head[k] ? h : k);
}
int dfs(int h, int id) {
  int n = a[h].size() - 1, x, res = 0;
  for (int i = 0; i <= n; ++i) {
    if (num[a[h][i].first] >= num[h] - 1) continue;
    if (!num[a[h][i].first]) {
      num[a[h][i].first] = num[h] + 1;
      x = dfs(a[h][i].first, a[h][i].second);
      if (!In[h].count(x)) res = re(res, x);
    } else {
      head[++ncyc] = num[a[h][i].first];
      cycIn[a[h][i].second] = ncyc;
      In[a[h][i].first].insert(ncyc);
      res = re(res, ncyc);
    }
  }
  return (cycIn[id] = res);
}
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> m;
  int x, y;
  for (int i = 1; i <= m; ++i) {
    cin >> x >> y;
    a[x].push_back(make_pair(y, i));
    a[y].push_back(make_pair(x, i));
  }
  num[1] = 2;
  dfs(1, 0);
  for (int i = 1; i <= m; ++i) {
    if (cycIn[i] && !dd[cycIn[i]]) result[++cnt] = i;
  }
  cout << cnt << '\n';
  for (int i = 1; i <= cnt; ++i) cout << result[i] << ' ';
}
