#include<iostream>
using namespace std;
#include<vector>
#include<algorithm>
struct bridge{
	vector<int>ord,low;
	vector<bool>art;
	vector<pair<int,int> >bridges;
	vector<vector<int> >G;
	bridge(int n_=0):ord(n_,-1),low(n_),art(n_,false),G(n_){}
	void add_edge(int u,int v)
	{
		G[u].push_back(v);
		G[v].push_back(u);
	}
	bool operator[](int a)const{return art[a];}
	bool is_bridge(int a,int b)const
	{
		if(ord[a]>ord[b])swap(a,b);
		return ord[a]<low[b];
	}
	void dfs(int u,int p,int&k)
	{
		low[u]=ord[u]=k++;
		for(int&v:G[u])
		{
			if(ord[v]==-1)
			{
				dfs(v,u,k);
				low[u]=min(low[u],low[v]);
				art[u]=art[u]|ord[u]<=low[v];
				if(ord[u]<low[v])bridges.push_back(u<v?make_pair(u,v):make_pair(v,u));
			}
			else if(v!=p)
			{
				low[u]=min(low[u],ord[v]);
			}
		}
	}
	void build()
	{
		int k=1,cnt=0;
		low[0]=ord[0]=0;
		for(int&v:G[0])if(ord[v]==-1)
		{
			dfs(v,0,k);
			if(ord[0]<low[v])bridges.push_back(make_pair(0,v));
			cnt++;
		}
		if(cnt>=2)art[0]=true;
	}
};
int N;
int u[1<<17],v[1<<17];
main()
{
	cin>>N;
	bridge P(N);
	for(int i=0;i<N;i++)
	{
		cin>>u[i]>>v[i];
		u[i]--,v[i]--;
		P.add_edge(u[i],v[i]);
	}
	P.build();
	vector<int>ans;
	for(int i=0;i<N;i++)if(!P.is_bridge(u[i],v[i]))ans.push_back(i+1);
	cout<<ans.size()<<endl;
	for(int i=0;i<ans.size();i++)cout<<ans[i]<<(i+1==ans.size()?"\n":" ");
}