#include <iostream>

int main()
{
  int n;
  std::cin >> n;
  bool isX = true;
  bool isY = true;
  int _x = 0;
  int _y = 0;
  
  std::cin >> _x >> _y;
  --n;
  
  while ((isX || isY) && n > 0)
  {
    int x = 0;
    int y = 0;
    std::cin >> x >> y;
    
    if (isX && x != _x)
    {
      isX = false;
    }
    
    if (isY && y != _y)
    {
      isY = false;
    }
    --n;
  }
  
  if (isX || isY)
  {
    std::cout << "YES\n";
  }
  else
  {
    std::cout << "NO\n";
  }
  
  return 0;
}