#include<bits/stdc++.h>
using namespace std;
set<int> s,ss;
int main()
 {
 	 int n;
 	  cin>>n;
 	  
 	   for(int i=0;i<n;i++)
 	   {
 	   	 int a,b;
 	   	  cin>>a>>b;
 	   	  s.insert(a);
 	   	  ss.insert(b);
		}
		if(s.size()==1 || ss.size()==1)
		 cout<<"YES"<<endl;
		 else cout<<"NO"<<endl;
 }