#include <fstream>

#include <iostream>

#include <vector>

 

using namespace std;

 

struct Node

{

          int friendsWith;

};

 

int main()

{

          ifstream in("S3.in");

          ofstream out("S3.out");

 

          vector<Node> allFriends(10000);

 

          int nFriends(0);

          in>>nFriends;

 

          for (int i=0; i< nFriends; i++)

          {

                    int f1(0);

                    int f2(0);

 

                    in>>f1;

                    in>>f2;

 

                    allFriends[f1].friendsWith = f2;

          }

 

          int f1(0);

          int f2(0);

 

          in>>f1;

          in>>f2;

 

          do

          {

                    int cntFri = allFriends[f1].friendsWith;

 

                    int seperation;

                    seperation = 0;

 

                    for (; cntFri != f2 || cntFri == f1; seperation++)

                    {

                              cntFri = allFriends[cntFri].friendsWith;

                              if (seperation > 10000)

                                        break;

                    }

 

                    if (cntFri != f1 && seperation < 10000)

                    {

                              out<<"Yes "<<seperation<<endl;

                    }

                    else

                    {

                              out<<"No"<<endl;

                    }

 

                    in>>f1;

                    in>>f2;

 

          } while (f1!=0 && f2!=0);

 

          in.close();

          out.close();

 

          return 0;

 

}