#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;

int N;
vector<int> G[100005];
map<pair<int,int>,int> memo;
int level[100005];
int parent[100005];
int reta, retb;

void dfs(int v, int l, int p){
  level[v] = l;
  parent[v] = p;

  rep(i,G[v].size()){
    if(reta != -1) return;
    
    int nxt = G[v][i];
    if(nxt == p) continue;

    if(level[nxt] != -1){
      reta = v;
      retb = nxt;
      return;
    }
    dfs(nxt, l+1, v);
  }
}


int main(){
  cin >> N;
  rep(i,N){
    int a, b;
    cin >> a >> b;
    memo[make_pair(a,b)] = i+1;
    memo[make_pair(b,a)] = i+1;
    G[a].push_back(b);
    G[b].push_back(a);
  }

  rep(i,100005){
    level[i] = -1;
    parent[i] = -1;
  }
  reta = -1;
  retb = -1;
  
  dfs(1, 0, -1);

  map<int,int> used;
  used[memo[make_pair(reta,retb)]] = 1;
  while(reta != retb){
    if(level[reta] > level[retb]){
      used[memo[make_pair(reta,parent[reta])]] = 1;
      reta = parent[reta];
    }
    else if(level[reta] < level[retb]){
      used[memo[make_pair(retb,parent[retb])]] = 1;
      retb = parent[retb];
    }
    else{
      used[memo[make_pair(reta,parent[reta])]] = 1;
      reta = parent[reta];
      used[memo[make_pair(retb,parent[retb])]] = 1;
      retb = parent[retb];
    }
  }

  vector<int> ret;
  REP(i,1,N+1){
    if(used.count(i) > 0) ret.push_back(i);
  }

  cout << ret.size() << endl;
  rep(i,ret.size()){
    if(i>0) cout << " ";
    cout << ret[i];
  }
  cout << endl;
  return 0;
}