#include <bits/stdc++.h>

using namespace std;

vector<pair<int, int> > ans;
int num = 0;
vector<bool> used(20000, false);
int timer, tin[20000], fup[20000];

void dfs (int v, int p, vector<vector<int> >& g){
    used[v] = true;
    tin[v] = fup[v] = timer++;
    for (int i = 0; i < g[v].size(); ++i) {
        int to = g[v][i];
        if (to == p)  continue;
        if (used[to])
            fup[v] = min (fup[v], tin[to]);
        else {
            dfs (to, v, g);
            fup[v] = min (fup[v], fup[to]);
            if (fup[to] > tin[v]){
                num++;
                ans.push_back({v, to});
            }
        }
    }
}

void find_bridges(int n, vector<vector<int> >& g){
    timer = 0;
    for (int i = 0; i < n; ++i)
        if (!used[i])
            dfs (i, -1, g);
}

bool compare(pair<int, int> a, pair<int, int> b){
    return(a.first == b.first && a.second == b.second || a.first == b.second && a.second == b.first);
}

int main() {
    int n, m, x, y;
    cin >> n >> m;
    vector<pair<int, int> > numbers(m);
    vector<vector<int> > g(n);
    vector<bool> used (n, false);
    for(int i = 0; i < m; i++){
        cin >> x >> y;
        g[x-1].push_back(y-1);
        g[y-1].push_back(x-1);
        numbers[i].first = x-1;
        numbers[i].second = y-1;
    }

    find_bridges(n, g);

    vector<int> ans1;
    for(int i = 0; i < ans.size(); i++) {
        int l = 0, nu = 0;
        for (int j = 0; j < m; j++)
            if (compare(ans[i], numbers[j])){
                l++;
                nu = j+1;
            }
        if(l == 1)
            ans1.push_back(nu);
        else
            num--;
    }
    cout << num << endl;
    sort(ans1.begin(), ans1.end());
    for(auto x : ans1)
        cout << x << " ";
    return 0;
}