//嘘解法
#include <iostream>
#include <vector>
using namespace std;
#define ll long long


int main(){
  ll N,A,B;
  cin>>N;
  vector<ll> d(N),ans;
  for(int i=0;i<N;i++){
    cin>>A>>B;
    if(d.at(A-1)==0){
      ans.push_back(A);
      d.at(A-1)=1;
    }
    else if(d.at(B-1)==0){
      ans.push_back(B);
      d.at(B-1)=1;
    }
  }
  if(ans.size()<N){
    cout<<"No\n";
    return 0;
  }
  cout<<"Yes\n";
  for(ll i:ans){
    cout<<i<<"\n";
  }
  return 0;
}