#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
#include <unordered_set>
#include <random>
#include <cassert>
#include <fstream>
#include <utility>
#include <functional>
#include <time.h>
#include <stack>
#include <array>
#define popcount __builtin_popcount
#define popcountll __builtin_popcountll
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;
struct TwoEdgeConnectedComponent{
	int n, k;
	vector<vector<int>> g, t;
	vector<bool> used;
	vector<int> comp, ord, low;
	using edge=pair<int, int>;
	vector<edge> br;
	void dfs(int x, int prev, int &c){
		used[x]=1;
		ord[x]=c++;
		low[x]=n;
		bool mul=0;
		for(auto y:g[x]){
			if(used[y]){
				if(y!=prev || mul) low[x]=min(low[x], ord[y]);
				else mul=1;
				continue;
			}
			dfs(y, x, c);
			low[x]=min(low[x], low[y]);
		}
	}
	void dfs2(int x, int num){
		comp[x]=num;
		for(auto y:g[x]){
			if(comp[y]!=-1) continue;
			if(ord[x]<low[y]){
				br.push_back({x, y});
				k++;
				dfs2(y, k);
			}else dfs2(y, num);
		}
	}
	TwoEdgeConnectedComponent(const vector<vector<int>> &g):g(g), n(g.size()), used(n), comp(n, -1), ord(n), low(n), k(0){
		int c=0;
		for(int i=0; i<n; i++){
			if(used[i]) continue;
			dfs(i, -1, c);
			dfs2(i, k);
			k++;
		}
	}
	void maketree(){
		t.resize(k);
		for(auto e:br){
			int x=comp[e.first], y=comp[e.second];
			t[x].push_back(y);
			t[y].push_back(x);
		}
	}
};
int main()
{
	int n; cin>>n;
	vector<vector<int>> g(n);
	int a[200020], b[200020];
	for(int i=0; i<n; i++){
		cin>>a[i]>>b[i];
		a[i]--; b[i]--;
		g[a[i]].push_back(b[i]);
		g[b[i]].push_back(a[i]);
	}
	TwoEdgeConnectedComponent myon(g);
	set<P> st;
	for(auto p:myon.br){
		st.insert(p);
		st.insert({p.second, p.first});
	}
	vector<int> ans;
	for(int i=0; i<n; i++){
		if(st.find({a[i], b[i]})==st.end()) ans.push_back(i);
	}
	cout<<ans.size()<<endl;
	for(auto x:ans) cout<<x+1<<" ";
	cout<<endl;
	return 0;
}