#include <string>
#include <vector>
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<stack>
#include<queue>
#include<cmath>
#include<algorithm>
#include<functional>
#include<list>
#include<deque>
#include<bitset>
#include<set>
#include<map>
#include<unordered_map>
#include<unordered_set>
#include<cstring>
#include<sstream>
#include<complex>
#include<iomanip>
#include<numeric>
#include<cassert>
#include<random>
#define X first
#define Y second
#define pb push_back
#define rep(X,Y) for (int (X) = 0;(X) < (int)(Y);++(X))
#define reps(X,S,Y) for (int (X) = (int)(S);(X) < (int)(Y);++(X))
#define rrep(X,Y) for (int (X) = (int)(Y)-1;(X) >=0;--(X))
#define rreps(X,S,Y) for (int (X) = (int)(Y)-1;(X) >= (int)(S);--(X))
#define repe(X,Y) for ((X) = 0;(X) < (Y);++(X))
#define peat(X,Y) for (;(X) < (Y);++(X))
#define all(X) (X).begin(),(X).end()
#define rall(X) (X).rbegin(),(X).rend()
#define eb emplace_back
#define UNIQUE(X) (X).erase(unique(all(X)),(X).end())
#define Endl endl
#define NL <<"\n"
#define cauto const auto

using namespace std;
using ll=long long;
using pii=pair<int,int>;
using pll=pair<ll,ll>;
template<class T> using vv=vector<vector<T>>;
template<class T> inline bool MX(T &l,const T &r){return l<r?l=r,1:0;}
template<class T> inline bool MN(T &l,const T &r){return l>r?l=r,1:0;}
//#undef NUIP
#ifdef NUIP
#include "benri.h"
#else
#define out(args...)
#endif
#ifdef __cpp_init_captures
template<typename T>vector<T> table(int n, T v){ return vector<T>(n, v);}
template <class... Args> auto table(int n, Args... args){auto val = table(args...); return vector<decltype(val)>(n, move(val));}
#endif
template<class A,class B> pair<A,B> operator+(const pair<A,B> &p,const pair<A,B> &q){ return {p.X+q.X,p.Y+q.Y};}
template<class A,class B,class C,class D> pair<A,B>& operator+=(pair<A,B> &p,const pair<C,D> &q){ p.X+=q.X; p.Y+=q.Y; return p;}
template<class A,class B> pair<A,B> operator-(const pair<A,B> &p,const pair<A,B> &q){ return {p.X-q.X,p.Y-q.Y};}
template<class A,class B,class C,class D> pair<A,B>& operator-=(pair<A,B> &p,const pair<C,D> &q){ p.X-=q.X; p.Y-=q.Y; return p;}
template<class A,class B> istream& operator>>(istream &is, pair<A,B> &p){ is>>p.X>>p.Y; return is;}
template<class T=ll> T read(){ T re; cin>>re; return move(re);}
template<class T=ll> T read(const T &dec){ T re; cin>>re; return re-dec;}
template<class T=ll> vector<T> readV(const int sz){ vector<T> re(sz); for(auto &x:re) x=read<T>(); return move(re);}
template<class T=ll> vector<T> readV(const int sz, const T &dec){ vector<T> re(sz); for(auto &x:re) x=read<T>(dec); return move(re);}
vv<int> readG(const int &n,const int &m){ vv<int> g(n); rep(_,m){ cauto a=read<int>(1),b=read<int>(1); g[a].pb(b); g[b].pb(a);} return move(g);}
vv<int> readG(const int &n){ return readG(n,n-1);}
const ll MOD=1e9+7; //998244353

class Bcc{
  vector<int> num,inS;
  stack<int> roots,st;
  int cnt;
public:
  vv<int> bcc,tree,tedge;
  vector<int> brdg,inv;
  void dfs(const vv<int> &g,const vector<pii> &es,int v,int e){
    num[v]=++cnt;
    st.push(v); inS[v]=1; roots.push(v);
    for(const int &i:g[v])if(i!=e){
				int w=es[i].X+es[i].Y-v;
				if(!num[w]){
					dfs(g,es,w,i);
				}else if(inS[w]){
					while(num[roots.top()]>num[w]) roots.pop();
				}
      }
    if(v==roots.top()){
      brdg.pb(e);
      bcc.pb(vector<int>());
      while(1){
				int w=st.top(); st.pop(); inS[w]=0;
				bcc.back().pb(w);
				if(v==w) break;
      }
      roots.pop();
    }
  }
  
  Bcc(vv<int> &g,vector<pii> es){
    const int n=g.size();
    num.resize(n); inS.resize(n);
    int cnt=0;
    rep(i,n)if(!num[i]){
      dfs(g,es,i,-1);
      brdg.pop_back();
    }
    const int m=bcc.size();
    inv.resize(n);
    rep(i,m) for(const int &v:bcc[i]) inv[v]=i;
    for(pii &p:es){p.X=inv[p.X]; p.Y=inv[p.Y];}
    //sort(all(es)); UNIQUE(es);
    tree.resize(m); tedge.resize(m);
    int i=0;
    for(const pii &p:es){
      if(p.X!=p.Y){
				tree[p.X].pb(p.Y);
				tree[p.Y].pb(p.X);
				tedge[p.X].pb(i);
				tedge[p.Y].pb(i);
      }
      ++i;
    }
  }
};

int main(){
  ios_base::sync_with_stdio(false); cin.tie(0);
  cout<<fixed<<setprecision(0);
	cauto n=read();
	cauto es=readV<pii>(n,{1,1});
	vv<int> g(n);
	rep(i,n){
		g[es[i].X].eb(i);
		g[es[i].Y].eb(i);
	}
	vector<int> isB(n);
	Bcc h(g,es);
	for(cauto b:h.brdg) isB[b]=1;
	vector<int> re;
	rep(i,n)if(!isB[i]) re.eb(i);
	cout<<re.size() NL;
	rep(i,n) cout<<re[i]+1<<" \n"[i+1==re.size()];
  return 0;
}