105

#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
#include <cstdio>
#include <set>
#include <map>
#include <sstream>
#include <iterator>
#include <cmath>
#include <unordered_map>
#include <queue>

using namespace std;

void dfs(int u, int p, int dep, vector< vector<int> > &g,
         vector<int> &d, vector<int> &fup, set<pair<int, int>> &bridges){
    d[u] = fup[u] = dep;
    for (int i = 0; i < g[u].size(); ++i){
        if(g[u][i] == p)
            continue;
        if(d[g[u][i]] != -1)
            fup[u] = min(fup[u], d[g[u][i]]);
        else{
            dfs(g[u][i], u, dep + 1, g, d, fup, bridges);
            fup[u] = min(fup[u], fup[g[u][i]]);
            if(fup[g[u][i]] > d[u])
                bridges.insert(make_pair(u, g[u][i]));
        }

    }
}

int main(){
    ios_base::sync_with_stdio(false);

    int n, m;
    cin >> n >> m;
    vector< vector<int> > g(n);
    map<pair<int, int>, int> edges;
    for (int i = 0; i < m; ++i){
        int x, y;
        cin >> x >> y;
        edges[make_pair(x - 1, y - 1)] = i;
        edges[make_pair(y - 1, x - 1)] = i;
        g[x - 1].push_back(y - 1);
        g[y - 1].push_back(x - 1);
    }

    vector<int> d(n, -1);
    vector<int> fup(n);
    set<pair<int, int>> bridges;
    for (int i = 0; i < n; ++i)
        if(d[i] == -1)
            dfs(i, i, 0, g, d, fup, bridges);

    vector<int> ans;
    for(auto it = bridges.begin(); it != bridges.end(); ++it)
        ans.push_back(edges[*it] + 1);
    sort(ans.begin(), ans.end());

    cout << ans.size() << endl;
    for (int i = 0; i < ans.size(); ++i)
        cout << ans[i] << " ";

    cout << endl;
    return 0;
}