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>
const int N = 100000 + 100;
const int mod = 1e9 + 7;
const int inf = 0x7fffffff;
using namespace std;
int n, m, xx, yy;
int tin[N], low[N], id = 0;
int Link[N], len = 0;
int iscut[N], bcc_cnt = 0, bccno[N];
vector<int> ans, bcc[100100];
struct node {
  int y, next, id;
} e[N * 2];
struct edge {
  int xx, yy, id;
};
stack<edge> st;
void add(int xx, int yy, int id) {
  e[++len].next = Link[xx];
  Link[xx] = len;
  e[len].y = yy;
  e[len].id = id;
}
void dfs(int u, int fa) {
  tin[u] = low[u] = ++id;
  int child = 0;
  for (int i = Link[u]; i; i = e[i].next) {
    int v = e[i].y;
    edge k = {u, v, e[i].id};
    st.push(k);
    if (!tin[v]) {
      child++;
      dfs(v, u);
      low[u] = min(low[u], low[v]);
      if (low[v] >= tin[u]) {
        set<int> bian;
        iscut[u] = 1;
        bcc_cnt++;
        bcc[bcc_cnt].clear();
        while (true) {
          edge x = st.top();
          st.pop();
          bian.insert(x.id);
          if (bccno[x.xx] != bcc_cnt) {
            bcc[bcc_cnt].push_back(x.xx);
            bccno[x.xx] = bcc_cnt;
          }
          if (bccno[x.yy] != bcc_cnt) {
            bcc[bcc_cnt].push_back(x.yy);
            bccno[x.yy] = bcc_cnt;
          }
          if (x.xx == u && x.yy == v) break;
        }
        if (bian.size() == bcc[bcc_cnt].size()) {
          set<int>::iterator it;
          for (it = bian.begin(); it != bian.end(); it++) ans.push_back(*it);
        }
      }
    } else if (tin[v] < tin[u] && v != fa)
      low[u] = min(low[u], tin[v]);
  }
  if (fa == 0 && child == 1) iscut[u] = 0;
}
int main() {
  scanf("%d %d", &n, &m);
  for (int i = 1; i <= m; i++) {
    scanf("%d %d", &xx, &yy);
    add(xx, yy, i);
    add(yy, xx, i);
  }
  for (int i = 1; i <= n; i++)
    if (!tin[i]) dfs(i, i);
  cout << ans.size() << endl;
  sort(ans.begin(), ans.end());
  for (int i = 0; i < ans.size(); i++) printf("%d ", ans[i]);
  printf("\n");
  return 0;
}
