You have to cross a large desert that is 1,000 km long. You have a horse and 3,000 apples. The horse can carry a maximum of 1,000 apples at any time. For every kilometer that the horse needs to travel, it eats one apple before it can start moving. What is the maximum number of uneaten apples that the horse can transport to the other end of the desert? Please provide detailed explanations with your answer.