#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define P pair<ll,ll>
#define FOR(I,A,B) for(ll I = ll(A); I < ll(B); ++I)
#define FORR(I,A,B) for(ll I = ll((B)-1); I >= ll(A); --I)
#define TO(x,t,f) ((x)?(t):(f))
#define SORT(x) (sort(x.begin(),x.end())) // 0 2 2 3 4 5 8 9
#define POSL(x,v) (lower_bound(x.begin(),x.end(),v)-x.begin()) //xi>=v  x is sorted
#define POSU(x,v) (upper_bound(x.begin(),x.end(),v)-x.begin()) //xi>v  x is sorted
#define NUM(x,v) (POSU(x,v)-POSL(x,v))  //x is sorted
#define REV(x) (reverse(x.begin(),x.end())) //reverse
ll gcd_(ll a,ll b){if(a%b==0)return b;return gcd_(b,a%b);}
ll lcm_(ll a,ll b){ll c=gcd_(a,b);return ((a/c)*b);}
#define NEXTP(x) next_permutation(x.begin(),x.end())
const ll INF=ll(1e16)+ll(7);
const ll MOD=1000000007LL;
#define out(a) cout<<fixed<<setprecision((a))
//tie(a,b,c) = make_tuple(10,9,87);
#define pop_(a) __builtin_popcount((a))
ll keta(ll a){ll r=0;while(a){a/=10;r++;}return r;}


struct Articulation_point_and_Bridge{
int V,E=0;
vector< vector<int> > G;
vector<int> ord,low;
vector<bool> vis;
vector< pair<int, int> > bridge;
vector<int> articulation;
Articulation_point_and_Bridge(int V_){
	V=V_;
	G.resize(V);
	ord.resize(V,0);
	low.resize(V,0);
	vis.resize(V,false);
}
void dfs(int v, int p, int &k){
	vis[v] = true;
	ord[v] = k++;
	low[v] = ord[v];
	bool isArticulation = false;
	int ct = 0;
	for (int i = 0; i < G[v].size(); i++){
		if (!vis[G[v][i]]){
			ct++;
			dfs(G[v][i], v, k);
			low[v] = min(low[v], low[G[v][i]]);
			if (~p && ord[v] <= low[G[v][i]]) isArticulation = true;
			if (ord[v] < low[G[v][i]]) bridge.push_back(make_pair(min(v, G[v][i]), max(v, G[v][i])));
		}
		else if (G[v][i] != p){
			low[v] = min(low[v], ord[G[v][i]]);
		}
	}
	
	if (p == -1 && ct > 1) isArticulation = true;
	if (isArticulation) articulation.push_back(v);
}
void add_edge(int v1,int v2){
	G[v1].push_back(v2);
	G[v2].push_back(v1);
	E++;
}
void calc(){
	int k=0;
	for(int i=0;i<V;i++){
		if(!vis[i])dfs(i,-1,k);
	}
	//sort(bridge.begin(), bridge.end());
	//sort(articulation.begin(), articulation.end());
}
};


int main(){

	ll N;
	cin >> N;

	Articulation_point_and_Bridge g(N);
	vector<pair<int,int>> all_b;
	FOR(i,0,N){
		ll a,b;
		cin >> a >> b;
		if(a>b)swap(a,b);
		g.add_edge(a-1,b-1);
		all_b.push_back({a-1,b-1});
	}

	g.calc();
	set<pair<int,int>> br;
	FOR(i,0,g.bridge.size()){
		br.insert(g.bridge[i]);
	}

	cout << N-g.bridge.size() << endl;
	bool s = false;
	FOR(i,0,N){
		if(not br.count(all_b[i])){
			if(s)cout << " ";
			cout << i+1;
			s = true;
		}
	}

}