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 = 1e5 + 9;
vector<pair<int, int>> adj[N];
int dfn[N], lowlink[N], vid;
bool inStk[N];
stack<pair<int, int>> stk;
map<pair<int, int>, int> mp;
set<int> ans;
int start;
void tarjan(int node, int edge) {
  dfn[node] = lowlink[node] = ++vid;
  inStk[node] = 1;
  stk.push({node, edge});
  for (auto it : adj[node]) {
    if (!dfn[it.first]) {
      tarjan(it.first, it.second);
      lowlink[node] = min(lowlink[node], lowlink[it.first]);
    } else if (inStk[it.first])
      lowlink[node] = min(lowlink[node], dfn[it.first]);
  }
  if (lowlink[node] == dfn[node]) {
    int x = -1;
    while (x != node) {
      if (x == -1) {
        x = stk.top().first;
        ans.insert(mp[{x, start}]);
      }
      x = stk.top().first;
      ans.insert(stk.top().second);
      stk.pop();
      inStk[x] = 0;
    }
  }
}
int main() {
  cout << fixed << setprecision(12), ios::sync_with_stdio(false),
      cin.tie(nullptr), cout.tie(nullptr);
  int n, m, u, v;
  cin >> n >> m;
  for (int i = 0; i < m; ++i) {
    cin >> u >> v;
    adj[u].push_back({v, i + 1});
    adj[v].push_back({u, i + 1});
    mp[{u, v}] = i + 1;
  }
  for (int i = 1; i <= n; ++i) {
    if (!dfn[i]) {
      start = i;
      tarjan(i, -1);
    }
  }
  ans.erase(ans.begin());
  cout << ans.size() << '\n';
  for (auto it : ans) cout << it << ' ';
  return 0;
}
