#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;

int main()
{
  ios::sync_with_stdio(false);
  int n;
  cin>>n;
  int x,y,newX,newY ;
  bool flagX = true , flagY = true;
  for(int i = 0 ; i < n ; i++)
  {
    cin>>newX>>newY;
    if(i > 0)
    {
      if(flagX && newX != x )
        flagX = false ;
      if(flagY && newY != y)
        flagY= false ;
    }
    x = newX;
    y = newY;
  }
  if(flagX || flagY)
    cout<<"YES";
  else
    cout<<"NO";

  return 0;
}