muteki_gakoi_movement = {
  '7 9' => '6 8',
  '2 8' => '5 8',
  '3 9' => '4 8'
}

movement = {}
gets.to_i.times do
  x1, y1, x2, y2 = gets.split.map(&:to_i)
  movement[[x1, y1].join(' ')] = [x2, y2].join(' ')
end

puts muteki_gakoi_movement.all? { |start_p, end_p|
  before, current = nil, start_p
  while current = movement[current]
    break true if current == end_p
    break false if before == movement[current]

    before = current
  end
} ? 'YES' : 'NO'