#include <bits/stdc++.h>

using namespace std;

using ll = long long;

constexpr char newl = '\n';

typedef pair<int, int> P;

vector< vector<int> > G;
vector<int> ord, low;
vector<P> bridge;

void dfs(int cur, int par, int& t) {
    ord[cur] = ++t;
    low[cur] = ord[cur];
    for (int nex : G[cur]) {
        if (nex == par) continue;
        if (ord[nex] == 0) {
            dfs(nex, cur, t);
            low[cur] = min(low[cur], low[nex]);
            if (ord[cur] < low[nex]) bridge.push_back(minmax(cur, nex));
        } else {
            low[cur] = min(low[cur], ord[nex]);
        }
    }
}

void bridges(int v) {
    ord.resize(v, 0);
    low.resize(v);
    int t = 0;
    dfs(0, -1, t);
}

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);

    int n;
    cin >> n;

    vector<int> a(n), b(n);
    G.resize(n);
    for (int i = 0; i < n; i++) {
        cin >> a[i] >> b[i];
        --a[i]; --b[i];
        if (a[i] > b[i]) swap(a[i], b[i]);
        G[a[i]].push_back(b[i]);
        G[b[i]].push_back(a[i]);
    }
    bridges(n);

    set<P> s(bridge.begin(), bridge.end());
    vector<int> ans;
    for (int i = 0; i < n; i++) {
        if (s.find(P(a[i], b[i])) == s.end()) ans.push_back(i + 1);
    }
    cout << ans.size() << newl;
    for (size_t i = 0; i < ans.size(); i++) {
        cout << ans[i] << " \n"[i + 1 == ans.size()];
    }

    return 0;
}