#include<bits/stdc++.h>
using namespace std;
int main()
{    
   int n;
   cin>>n;
  
   set<int> s1;
   set<int> s2;
   for(int i=1;i<=n;i++)
   {  int x1,y1;
      cin>>x1>>y1;
      s1.insert(x1);
      s2.insert(y1);
   }
   if(s1.size()==1||s2.size()==1)
   cout<<"YES";
   else
   cout<<"NO";



















return 0;
}