#include <bits/stdc++.h>
#pragma GCC optimize("Ofast")
#define _GLIBCXX_DEBUG
using namespace std;
using std::cout;
using std::cin;
using std::endl;
using ll=long long;
using ld=long double;
ll ILL=1167167167167167167;
const int INF=2100000000;
const ll mod=1e9+7;
#define rep(i,a) for (ll i=0;i<a;i++)
template<class T> using _pq = priority_queue<T, vector<T>, greater<T>>;
template<class T> ll LB(vector<T> &v,T a){return lower_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> ll UB(vector<T> &v,T a){return upper_bound(v.begin(),v.end(),a)-v.begin();}
template<class T> bool chmin(T &a,const T &b){if(a>b){a=b;return 1;}else return 0;}
template<class T> bool chmax(T &a,const T &b){if(a<b){a=b;return 1;}else return 0;}
template<class T> void So(vector<T> &v) {sort(v.begin(),v.end());}
template<class T> void Sore(vector<T> &v) {sort(v.begin(),v.end(),[](T x,T y){return x>y;});}
void yneos(bool a){if(a) cout<<"YES\n"; else cout<<"NO\n";}

namespace po167{
struct UFtree
{
	std::vector<int> wei;
	std::vector<int> q;
	int component;
	UFtree(int n):wei(n),component(n),par(n){
		for(int i=0;i<n;i++){
			wei[i]=1,par[i]=i;
		}
	}
	void intialize(){
		for(auto x:q){
			wei[root(x)]=1;
			par[x]=x;
		}
		component=(int)par.size();
		q={};
	}
	//根っこを返す
	int root(int a){
		if(a==par[a]) return a;
		return par[a]=root(par[a]);
	}
	//trueなら1,falseなら0
	int same(int a,int b){
		if(root(a)==root(b)) return 1;
		else return 0;
	}
	//a,bが違う根っこの元なら結合する,結合したらtrueを返す
	bool unite(int a,int b){
		a=root(a),b=root(b);
		if(a==b) return false;
		if(wei[a]<wei[b]) std::swap(a,b);
		par[b]=a;
		q.push_back(b);
		wei[a]+=wei[b];
		component--;
		return true;
	}
	private:
	std::vector<int> par;
};
}
using po167::UFtree;


void solve();
// oddloop
int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int t=1;
	//cin>>t;
	rep(i,t) solve();
}

void solve(){
	int N;
	cin>>N;
	map<pair<int,int>,int> m;
	UFtree T(N);
	int x=0,y=0,a,b;
	vector<int> ans;
	vector<vector<int>> G(N);
	rep(i,N){
		cin>>a>>b;
		a--,b--;
		m[{a,b}]=i+1;
		m[{b,a}]=i+1;
		if(!T.unite(a,b)){
			ans.push_back(i+1);
			x=a,y=b;
		}else{
			G[a].push_back(b);
			G[b].push_back(a);
		}
	}
	vector<int> order={0},seen(N),pare(N,-1);
	pare[0]=-2;
	rep(i,N){
		a=order[i];
		for(int c:G[a]){
			if(pare[c]==-1){
				pare[c]=a;
				seen[c]=seen[a]+1;
				order.push_back(c);
			}
		}
	}
	if(seen[x]>seen[y]) swap(x,y);
	while(seen[y]!=seen[x]){
		ans.push_back(m[{y,pare[y]}]);
		y=pare[y];
	}
	while(x!=y){
		ans.push_back(m[{y,pare[y]}]);
		y=pare[y];
		ans.push_back(m[{x,pare[x]}]);
		x=pare[x];
	}
	So(ans);
	cout<<ans.size()<<"\n";
	rep(i,(int)ans.size()){
		if(i) cout<<" ";
		cout<<ans[i];
	}
	cout<<"\n";
}