#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

class Bridge {
  struct Edge {
    int src, dest, idx;
    Edge(int src, int dest, int idx):src(src),dest(dest),idx(idx){}
  };
  
  int N;
  int M;
  vector<vector<Edge>> G;
  vector<int> parent, parent_edge_idx;
  vector<int> imos;

  map<int,bool> cycle_edges;
  
  void dfs(int v, int p, int edge_idx){
    parent[v] = p;
    parent_edge_idx[v] = edge_idx;

    for(Edge& e : G[v]){
      int nxt = e.dest;
      if(nxt == p) continue;
      if(cycle_edges.count(e.idx) > 0) continue;
      if(parent[nxt] != -2){
        imos[v]++;
        imos[nxt]--;
        cycle_edges[e.idx] = true;
      }else{
        dfs(nxt, v, e.idx);
      }
    }
  }

  int dfs2(int v, int p){
    int ret = imos[v];
    for(Edge& e : G[v]){
      int nxt = e.dest;
      if(nxt == p) continue;
      if(cycle_edges.count(e.idx) > 0) continue;
      ret += dfs2(nxt, v);
    }

    if(ret > 0){
      cycle_edges[parent_edge_idx[v]] = true;
    }
    return ret;
  }
  
public:
  Bridge(int N):N(N),G(N),parent(N,-2),parent_edge_idx(N,-1),imos(N,0){}

  void add_edge(int src, int dest, int idx){
    G[src].emplace_back(src,dest,idx);
    G[dest].emplace_back(dest,src,idx);
    M++;
  }

  vector<int> solve(){
    dfs(0,-1,-1);
    dfs2(0,-1);

    vector<int> ret;
    rep(i,M){
      if(cycle_edges.count(i) == 0) ret.push_back(i);
    }
    return ret;
  }
};


int main(){
  int N;
  cin >> N;
  Bridge bridge(N);
  rep(i,N){
    int a, b;
    cin >> a >> b;
    a--; b--;
    bridge.add_edge(a,b,i);
  }

  vector<int> ret = bridge.solve();
  map<int,int> memo;
  rep(i,ret.size()) memo[ret[i]] = 1;
  vector<int> cycles;
  rep(i,N) if(memo.count(i) == 0) cycles.push_back(i+1);
  
  cout << cycles.size() << endl;
  rep(i,cycles.size()){
    if(i>0) cout << " ";
    cout << cycles[i];
  }
  cout << endl;
  
  
  return 0;
}