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 mn = 1e5 + 7;
int n, m, u[mn], v[mn], cnt, dph[mn], siz[mn], fa[mn];
bool vis[mn];
vector<int> to[mn], ans;
void dfs(int x, int f) {
  dph[x] = dph[f] + 1;
  fa[x] = f;
  for (int i = 0; i < to[x].size(); ++i) {
    int t = to[x][i];
    if (t == f) continue;
    if (!dph[t])
      dfs(t, x);
    else if (dph[t] < dph[x]) {
      siz[t]--;
      siz[x]++;
    }
  }
}
void get_siz(int x) {
  if (vis[x]) return;
  vis[x] = 1;
  for (int i = 0; i < to[x].size(); ++i) {
    int t = to[x][i];
    if (vis[t]) continue;
    get_siz(t);
    siz[x] += siz[t];
  }
}
int main() {
  scanf("%d%d", &n, &m);
  for (int i = 1; i <= m; ++i) {
    scanf("%d%d", &u[i], &v[i]);
    to[u[i]].push_back(v[i]);
    to[v[i]].push_back(u[i]);
  }
  dfs(1, 0);
  get_siz(1);
  for (int i = 1; i <= m; ++i) {
    if (dph[u[i]] < dph[v[i]]) swap(u[i], v[i]);
    if (fa[u[i]] == v[i]) {
      if (siz[u[i]] == 1) {
        ans.push_back(i);
        cnt++;
      }
    } else {
      int x = u[i], ed = v[i], flag = 1;
      while (x != ed) {
        if (siz[x] != 1) {
          flag = 0;
          break;
        }
        x = fa[x];
      }
      if (flag) {
        ans.push_back(i);
        cnt++;
      }
    }
  }
  printf("%d\n", cnt);
  for (int i = 0; i < ans.size(); ++i) printf("%d ", ans[i]);
}
