#include <bits/stdc++.h>
#define f first
#define s second
using namespace std;
int n, m, B = 0, q, pro[20001], gaa[20001], ff, i;
vector<pair<int, int>> aaa;
vector<pair<int, int>> deeed;
vector<vector<int>> zokeri;
vector<bool> ystal(20001, 0);
vector<int> konec;
void dfs (int xi, int ggvp)
{
    ystal[xi] = 1;
    pro[xi] = q++;
    gaa[xi] = q++;
    for (i = 0; i < zokeri[xi].size(); i++)
    {
        ff = zokeri[xi][i];
        if (ff == ggvp)
            continue;
        if (ystal[ff])
            gaa[xi] = min(gaa[xi], pro[ff]);
        else
        {
            dfs (ff, xi);
            gaa[xi] = min(gaa[xi], gaa[ff]);
            if (gaa[ff] > pro[xi])
            {
                B++;
                deeed.push_back({xi, ff});
            }
        }
    }
}
int main()
{
    int b, e, j, glhf, niay;
    cin >> n >> m;
    aaa.resize(m);
    zokeri.resize(n);
    for(i = 0; i < m; i++)
    {
        cin >> b >> e;
        zokeri[b - 1].push_back(e - 1);
        zokeri[e - 1].push_back(b - 1);
        aaa[i].f = b - 1;
        aaa[i].s = e - 1;
    }
    for (i = 0; i < n; i++)
    {
        if (!ystal[i])
            dfs (i, -1);
    }
    for(i = 0; i < deeed.size(); i++)
    {
        glhf = 0, niay = 0;
        for (j = 0; j < m; j++)
        {
            if (((deeed[i].f == aaa[j].f) and (deeed[i].s == aaa[j].s)) or ((deeed[i].f == aaa[j].s) and (deeed[i].s == aaa[j].f)))
            {
                glhf++;
                niay = j+1;
            }
        }
        if(glhf == 1)
            konec.push_back(niay);
        else
            B--;
    }
    cout << B << "\n";
    sort(konec.begin(), konec.end());
    for(auto N : konec)
        cout << N << " ";
}